全文获取类型
收费全文 | 207篇 |
免费 | 9篇 |
专业分类
林业 | 27篇 |
农学 | 10篇 |
基础科学 | 1篇 |
50篇 | |
综合类 | 15篇 |
农作物 | 11篇 |
水产渔业 | 22篇 |
畜牧兽医 | 47篇 |
园艺 | 9篇 |
植物保护 | 24篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 20篇 |
2013年 | 11篇 |
2012年 | 19篇 |
2011年 | 17篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有216条查询结果,搜索用时 15 毫秒
81.
Paulina Nowicka Aneta Wojdyło Piotr Laskowski 《Plant foods for human nutrition (Dordrecht, Netherlands)》2018,73(4):314-320
The presented study provides important insights on the health properties of Prunus persica fruit related to their polyphenol and carotenoid profiles, antioxidant capacity and in vitro potential to inhibit enzymes relevant to type 2 diabetes (α-amylase, α-glucosidase) and obesity (pancreatic lipase) management. Such results have not been published so far. The study showed substantial differences in the chemical composition of peach fruit depending on the cultivar. At the same time, it demonstrated some common features of selected cultivars - the varieties with light flesh (‘Spring Time’; ‘Madison’) were characterized by a high content of phenolic acids and flavonols, thus exhibiting high activity against α-amylase, while the yellow varieties with high content of carotenoids (‘Harrow Diamond’; ‘Harrow Beauty’) showed high inhibitory activity toward porcine pancreatic lipase. Finally, it has been shown that peach fruit is an interesting raw material with a varied chemical composition and nutritional value, especially with high inhibitory potential against digestive enzymes linked to obesity and type 2 diabetes, strongly determined by the cultivar. 相似文献
82.
Piotr Gąsiorek Daniel Stec Witold Morek Jamila Marnissi Łukasz Michalczyk 《African Zoology》2017,52(2):77-89
The current knowledge of the diversity and distribution of tardigrade species in northern Africa is scarce and far from satisfactory. In this paper we review old and provide new faunistic records for various regions of Tunisia. Among the newly recorded taxa, we found a new heterotardigrade Bryodelphax maculatus sp. nov. The new species belongs to the weglarskae group, characterised by the presence of ventral plates, but differs from its congeners by a different arrangement of ventral plates and by conspicuous groups of cuticular tubercles on the ventral cuticle. The analysis of larval, juvenile and mature instars of the new species revealed, for the first time in heterotardigrades, ontogenetic variability in the development of ventral armature.
http://zoobank.org/urn:lsid:zoobank.org:pub:7EA21201-8C74-4BFD-8EAF-A131A78805F0 相似文献
83.
Piotr Zapotoczny 《Journal of Cereal Science》2011,54(1):60-68
The development of non-destructive methods for the evaluation of cereal grain varieties has important implications for the food processing industry. The described experiment investigated 11 varieties of spring and winter wheat of different quality class. The analysis was performed on images acquired from a flatbed scanner interfaced to a PC. Kernel images were digitalized at high resolution (2673 × 4031) with 24-bit depth and 400 dpi. The variables input into the statistical model were the textures of single kernel projections. Textures were computed separately for seven channels (R, G, B, Y, S, U, V). The results were examined with the application of discriminant analysis and neural networks. The accuracy of texture-based classification of 11 wheat varieties reached 100%. The experimental design which yielded the most satisfactory results comprised texture measurements from the combined area of 20 kernels and variables from seven channels input into the neural network. The final classification quality was not affected by the year of cultivation, moisture content or grain variety. 相似文献
84.
Susceptibility of apple genotypes from European genetic resources to fire blight (Erwinia amylovora)
85.
Maria Skłodowska Ewa Gajewska Elżbieta Kuźniak Artur Mikiciński Piotr Sobiczewski 《Scientia Horticulturae》2010
BTH (S-methylbenzo-1,2,3-thiadiazole-7-carbothiate), an active compound of the commercial preparation Bion, has been studied as an elicitor of resistance to fire blight (Erwinia amylovora) in apple. However, the biochemical mechanisms of its action are not fully elucidated. Our study indicated that BTH at the best time of its protection activity (2–14 days after application) induced changes in prooxidant–antioxidant balance in the leaves of apple trees, but in different ways in the enzymatic and nonenzymatic antioxidants. Glutathione as low molecular antioxidant as well as superoxide anion radical and lipid peroxides as oxidants exhibited changes at the early phase of BTH action. Glutathione-dependent enzymes were strongly affected by the elicitor used. On the 2nd day glutathione transferase (GST) and glutathione peroxidase (GSH-Px) activities increased by about 70% and 30% above the control, respectively. GST activity normalized about the 14th day but GSH-Px at the same time showed 27% of the control value. Among enzymes utilising hydrogen peroxide only catalase showed increase (37%) at the early phase of experiment. Compared with the control, BTH-treated plants did not show changes in ascorbate peroxidase and phenylalanine ammonia-lyase activities. Tocopherol (TOC) level diminished starting from the 7th day after BTH treatment and on the 14th day it was only 28% of the control. It is proposed that extinguishing of BTH-mediated signal resulted from TOC and glutathione action. The diminished ascorbate level at all examined times may play a crucial role in BTH-mediated cell growth regulation. The direct influence of BTH on lipid metabolism should be also taken into consideration. 相似文献
86.
Wojciech Mrozik Christian Jungnickel Tomasz Ciborowski William Robert Pitner Jolanta Kumirska Zbigniew Kaczyński Piotr Stepnowski 《Journal of Soils and Sediments》2009,9(3):237-245
Background, aim, and scope Ionic liquids (ILs) are a new class of alternative solvents that make ideal non-volatile media for a variety of industrial
processes such as organic synthesis and biocatalysis, as alternative electrolytes, as phases and phase modifications in separation
techniques, and as alternative lubricants. Once the large-scale implementation of ILs begins, the industrial application will
follow. In view of their great stability, they could slip through classical treatment systems to become persistent components
of the environment, where the long-term consequences of their presence are still unknown. Sorption on soils has a critical
effect on the transport, reactivity, and bioavailability of organic compounds in the environment. So far, the IL sorption
mechanism was investigated solely on the basis of batch experiments, which precluded any assessment of the dynamics of the
process. An understanding of the mobility of ILs in soil columns is crucial for an accurate prediction of their fate in the
soil. The aim of this study therefore was to investigate in detail the mobility of selected imidazolium ILs on three soil
types. Moreover, it was decided to study these processes in soils from the coastal region (Gdańsk, Poland), which usually
constitute a very important geochemical compartment, participating in the transport of contaminants on their way to the sea.
Materials and methods The mobility of alkylimidazolium ILs was investigated in columns containing soils from the coastal area. In addition, the
sorption processes in all the soil systems studied were described isothermally and the equilibrium sorption coefficient was
evaluated. The sorption capacities were determined according to OECD guidelines. Sorption dynamics was studied with use of
polypropylene columns (diameter—10 mm, height—100 mm) packed with 10 g of soil. The ionic liquid solution was then injected
into the soil column and left for 24 h to equilibrate. After this, a solution of 0.01 mM CaCl2 was pumped through the column at a rate of 0.3 ml min–1. Effluents were collected from the bottom of the column and analyzed by HPLC.
Results Sorption was strongest on the Miocene silt and the alluvial agricultural soil and weakest on the podsolic soil and Warthanian
glacial till. The K
d value of long-chain ILs was far higher than that of the short-chain ones. Among the substances tested, hydroxylated ILs were
usually more weakly sorbed. Desorption of ILs is inversely correlated with sorption intensity. The experimental results of
the column tests correlate well with those from batch experiments. In the cases of weakly binding soils, ILs were detected
almost immediately in the eluent. The elution profiles of long-chain ILs indicate that these compounds are very strongly sorbed
onto most soils, although certain amounts were transported through the soil. ILs exhibit a certain mobility in soils: in particular,
salts with short and/or hydroxylated side chains are extremely mobile.
Discussion The results indicate a stronger binding of ILs in the first sorption layer; once the first layer is saturated, there are no
more active sites on the soil surface (no free charged groups); hence, there are no more strong electrostatic binding sites,
and dispersive interaction becomes the dominant interaction potential. The influence of the structure of the ILs, especially
the side-chain length was also confirmed: The K
d value of long-chain ILs was far higher than that of the short-chain ones. The long alkyl side chain facilitates dispersive
interactions with soil organic matter and intermolecular binding, and the build-up of a second layer becomes possible. Among
the substances tested, hydroxylated ILs were usually more weakly sorbed. The hydroxyl group in the side chain can alter the
polarity of the compound so strongly that interaction with organic matter hardly occurs; these salts then remain in the aqueous
phase. The experimental results from the column tests correlate well with those from batch tests. In the weakly binding soils
(with low organic matter), the only binding to the soil surface must be via electrostatic interactions, although intermolecular
van der Waals (ionic liquid–ionic liquid) interactions could also be taking place. The elution profile maxima for organic
rich soils are far smaller than for the other soils. In the former, hydrogen bonding, dispersive and π…π interactions play
a more important part than electrostatic interactions. The rapidly “disappearing” maxima of the elution peaks may indicate
that, after elution of ILs from the second layer, it is difficult to extract further sorbed ILs. In the first layer, the ILs
are bound by much stronger electrostatic interactions. To break these bonds, a greater energy is required than that sufficient
to extract ILs from double sorption layers. Results indicate, moreover, that hydrophobic ILs will be sorbed in the first few
centimeters of the soil; migration into the soil will therefore be almost negligible.
Conclusions Sorption of ILs was the strongest in soils with the highest cation exchange capacities and a high organic content. ILs were
also more strongly bound to the first sorption layer. The sorption coefficients of long-chain ILs were far higher than those
of short-chain ones; usually, hydroxylated derivatives were the least strongly sorbed. Results of soil column experiments
to investigate the mobility of ILs in soils correlated well with those from batch tests, and the elution profiles were also
well correlated with organic matter content. The observed rapidly disappearing elution peak maxima probably indicate that,
after elution of the ILs from the second layer, it is difficult to extract further sorbed compounds.
Recommendations and perspectives Obtained results gave an interesting insight into mobility of ionic liquids in soil columns. However, several questions are
now opened. It is therefore necessary to undertake further studies focused on total cycle of ionic liquids in the soil environment.
This should include their evapotrasporation (lysimeter test), bioaccumulation by plants as well as degradation and transformation
processes (chemical, biological, and physical) typically occurring in soils. Moreover, a further risk assessment of ILs is
desirable since this study has indicated that these compounds, especially those with low lipophilicities, are generally mobile
in the soil matrix. It is already known that short-chain ILs are characterized by low toxicities; should they enter the environment,
they will probably migrate within the soil and pose a risk of contamination of surface and ground waters. This topic is relevant
to the audience. Environmental threat of short-chain ionic liquids is currently unknown. From the predictive point of view,
judging on known low acute toxic effects or high polarities of these compounds seems to be not enough to confirm their “environmental
friendliness”. If we are to fully understand the potential environmental effects, one should also have an insight into long-term
biological consequences of these ionic liquids, including chronic toxicity tests, bioaccumulation, and biotransformation rates
as well as stability against natural elimination mechanisms. 相似文献
87.
Jan Bocianowski Kamila Nowosad Piotr Szulc 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2019,69(1):75-81
The objective of this study was to assess soil tillage methods by years interaction for harvest index (HI) of maize (Zea mays L.) grown in West Poland by the additive main effects and multiplicative interaction model. The study comprised four soil tillage methods, analysed in 12 years through field trials arranged in a randomised complete block design, with four replicates. HI of the tested soil tillage methods varied from 0.354 to 0.692 throughout the 12 years, with an average of 0.530. In the variance analysis, 57.06% of the total harvest index variation was explained by years, 2.39% by differences between soil tillage methods, and 8.71% by soil tillage methods by years interaction. HI is highly influenced by year factors. The method of reduced conventional tillage [autumn shallow ploughing (15 cm), cultivator with string roller in spring] was the most stable (additive main effects and multiplicative interaction stability value, ASV=0.410) for the HI values among studied soil tillage methods. This result confirms the opinion on the possibility of shallowing autumn ploughing in the cultivation of maize for grain. 相似文献
88.
Jaworska Magdalena Gorczyca Anna Sepiol Jadwiga Tomasik Piotr 《Water, air, and soil pollution》1997,93(1-4):157-166
The effect of sixteen metal ions: Al, Cd, Co(II), Cr(III), Cr(VI), Cu(II), Fe(III), Li, Mg, Mn(II), Mo(VI), Ni(II), Pb(II), Se(IV), V(V), and Zn on the mortality and infectivity ofHeterorhabditis bacteriophora were observed over a 96 hr period. All ions except Pb(II) even at naturally unrealistic concentrations did not cause the mortality of the nematodes. A weak vitalizing effect could eventually be observed with Mn(II), Mg, Fe(III) and Ni(II) (Table 1). However, such treatment generally lowered infectivity of the nematodes with respect to wax moth caterpillars.Galleria mellonella. This effect was particularly significant with Ni(II) and Pb(II). 相似文献
89.
Context
How do young birds achieve spatial knowledge about the environment during the initial stages of their life? They may follow adults, so gaining social information and learning; alternatively, young birds may acquire knowledge of the environment themselves by experiencing habitat and landscape features. If learning is at least partially independent of adults then young birds should respond to landscape composition at finer spatial scale than adults, who possess knowledge over a larger area.Objectives
We studied the responses of juvenile, immature and adult Caspian Gull Larus cachinnans to the same habitat and landscape variables, but at several spatial scales (ranging from 2.5 to 15 km), during post-breeding period.Methods
We surveyed 61 fish ponds (foraging patches) in southern Poland and counted Caspian gulls.Results
Juvenile birds responded at finer spatial scales to the factors than did adults. Immature birds showed complicated, intermediate responses to spatial scale. The abundance of juvenile birds was mostly correlated with the landscape composition (positively with the cover of corridors and negatively with barriers). Adult abundance was positively related to foraging patch quality (fish stock), which clearly required previous spatial experience of the environment. The abundance of all age classes were moderately correlated with each other indicating that social behaviour may also contribute to the learning of the environment.Conclusions
This study shows that as birds mature, they respond differently to components of their environment at different spatial scales. This has considerable ecological consequences for their distribution across environments.90.
Phagocytic and oxidative burst activity of phagocytic cells in peripheral blood and uterine washings in cows with clinical endometritis before and after intrauterine use of cephapirin and methisoprinol
下载免费PDF全文
![点击此处可从《Animal Science Journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Piotr Brodzki Urszula Lisiecka Adam Brodzki Renata Pyz‐Łukasik Leszek Krakowski 《Animal Science Journal》2018,89(10):1389-1397
The aim of the study was to evaluate phagocytic and killing activity of phagocytic cells in blood and uterine flush of cows with endometritis before and after intrauterine (i.u.) administration of cephapirin and methisoprinol. The research was carried out on 28 cows with clinical endometritis. Animals were divided into four groups, each composed of seven cows, depending on the i.u. treatment used: Group A—cephapirin; Group B—methisoprinol; Group C—cephapirin and methisoprinol at the same time; and a control group—without medication. Using flow cytometry technique, the phagocytic activity of granulocytes and monocytes was identified, as well as the oxidative burst activity of neutrophils in the peripheral blood and uterine washings. Summarizing the results of the research, i.u. infusion of cephapirin caused a reduction in the phagocytic and killing activity of phagocytes. The i.u. use of methisoprinol increased phagocytic and killing activity of phagocytes in the uterus. Administering both listed substances simultaneously showed a decrease in phagocytosis, presumably due to the dominating inhibitor effect of the antibiotic. However, also an increase of mean fluorescence intensity was observed, presumably caused by the methisoprinol. Intrauterine use of immunostimulatory substances, can improve the effectiveness of the treatment of endometritis in cows. 相似文献