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排序方式: 共有218条查询结果,搜索用时 20 毫秒
91.
Andrzej K. Siwicki Zdzisław Zakęś John C. Fuller Jr Steven Nissen Krzysztof Kazuń Edward Głąbski 《Aquaculture International》2006,14(1-2):153-161
$\upbeta$ -Hydroxy- $\upbeta$ -methyl butyrate (HMB) has been shown to counteract many of the negative effects of intensive fish production methods and results in increased growth and protection against diseases. In the present study, the in vitro and in vivo effect of HMB on the immunocompetence cell activity in tench Tinca tinca (L.) was examined. In the in vitro study pronephric phagocytes and lymphocytes were isolated from the fish and grown in culture medium (RPMI-1640) containing 0, 0.1, 1, 5, 10, 25, 50 or $100\,\upmu$ g HMB cm?3 of medium. The effects of HMB on the respiratory burst activity (RBA), the potential killing activity (PKA) and lymphocyte proliferation stimulated by concanavalin A (ConA) or lipopolysaccharide (LPS) were examined. The in vitro study showed that HMB increased the RBA and PKA of the phagocytes, compared to the medium over that of cells grown without HMB. Lymphocyte proliferation stimulated by ConA and LPS was also increased approximately when HMB was added to the culture medium at concentrations between 10 and $100\,\upmu$ g HMB cm?3. In the in vivo study fish were fed daily with pellets containing HMB at doses 0, 10, 25 and 50 mg kg?1 body weight day?1. The study showed that HMB statistically increased the RBA and PKA and highest activity at 50 mg kg?1 body weight day?1 were observed. Also lymphocyte proliferation stimulated by ConA and LPS were maximally stimulated at dose 50 mg kg?1 body weight day?1. In conclusion, the current study shows that HMB could potentially improve immunocompetence cell activity in tench through increased cell proliferation and functionality. 相似文献
92.
Tomasz Warzecha Andrzej Zieliński Edyta Skrzypek Tomasz Wójtowicz Maria Moś 《Phytoparasitica》2012,40(1):29-36
Vigor and selected physiological parameters (content of phenolic compounds, soluble sugars, chlorophyll a and b, and carotenoids)
of eight naked and two husked oat cultivars harvested at 15% moisture content were determined. Oat seeds were threshed using
two rotational speeds of the threshing drum: 1.6 m s−1 (LS) and 2.4 m s−1 (HS). They were then inoculated with a medium pathogenicity strain of Fusarium culmorum, strain IPO 348–01. In naked cultivars, the use of HS resulted in more severe mechanical damage; in consequence, seedling
vigor decreased by 16%. In naked cultivars chlorophyll a and b and carotenoids content were significantly reduced—by more
than 64%—when the HS was used. The inoculation caused over a 100% increase of carbohydrates in roots at LS but only a slight
increase at HS. Phenolic compound content was twice as high in roots than in leaves after inoculation for both LS and HS.
Area of microdamage and reduction of root fresh weight (f.wt.) are significantly correlated with biochemical parameters. Smaller
microdamage area and root f.wt. reduction are connected with higher physiological parameters, which confirms lower seedling
susceptibility to pathogen infection. 相似文献
93.
Chlorogenic acid is a naturally occurring phenolic compound found in all higher plants. This component, being the ester of caffeic acid with quinic acid, is an important biosynthetic intermediate and plays an important role in the plant's response to stress. Potential uses of chlorogenic acid are suggested in pharmaceuticals, foodstuffs, feed additives, and cosmetics due to its recently discovered biomedical activity. This finding caused new interest in chlorogenic acid properties, its isomers, and its natural occurrence. It has been found that as many as nine compounds (chlorogenic acid derivatives and its reaction product with water) can be formed from 5-o-caffeoylquinic acid during the heating of its water solution. Three of them, two hydroxylated 5-o-caffeoylquinic acid derivatives and 4,5-dicaffeoylquinic acid, have been not reported, yet. The amount of each formed component depends on the heating time and temperature. The presented results are important for researchers investigating plant metabolism and looking for new plant components. The transformation product can be mistakenly treated as a new component, not found before in the examined plant, or can be a cause of erroneous quantitative estimations of plant composition. 相似文献
94.
Andrzej Anioł 《Euphytica》1996,92(1-2):155-162
Summary The aluminium accumulation pattern was studied in roots and root tips of rye seedlings from two inbred lines, differing in Al-tolerance and their F1 hybrid.This investigations were undertaken in order to find whether the mechanism preventing root tips from to high Al-accumulation and damage to apical meristem observed in Al-tolerant isoline of wheat is also operating in rye. Al-uptake into the root tissue was studied in nutrient solution experiments during 24 h of incubation in solution containing aluminium. After Al-incubation roots were harvested, separated into root tips and basal parts, and aluminium content in root tissue was determined after wet digestion using catechol violet colorimetric method. It was found, that at low external Al-concentration in rye roots the mechanism preventing root tips from Al-accumulation and Al-damage operates, similarly as in Al-tolerant wheat isoline. But contrary to wheat in rye seedlings functioning of this mechanism was observed in both Al-tolerant and Al-sensitive lines. It is concluded that observed mechanism of the inhibition of Al-accumulation in apical part of roots plays much more important role in Al-tolerance mechanism in wheat than in rye.Abbreviations EDTA
ethylenediaminetetraacetic acid
- NIL
near-isogenic line 相似文献
95.
Why asparagine needs carbohydrates to generate acrylamide 总被引:15,自引:0,他引:15
Yaylayan VA Wnorowski A Perez Locas C 《Journal of agricultural and food chemistry》2003,51(6):1753-1757
Structural considerations dictate that asparagine alone may be converted thermally into acrylamide through decarboxylation and deamination reactions. However, the main product of the thermal decomposition of asparagine was maleimide, mainly due to the fast intramolecular cyclization reaction that prevents the formation of acrylamide. On the other hand, asparagine, in the presence of reducing sugars, was able to generate acrylamide in addition to maleimide. Model reactions were performed using FTIR analysis, and labeling studies were carried out using pyrolysis-GC/MS as an integrated reaction, separation, and identification system to investigate the role of reducing sugars. The data have indicated that a decarboxylated Amadori product of asparagine with reducing sugars is the key precursor of acrylamide. Furthermore, the decarboxylated Amadori product can be formed under mild conditions through the intramolecular cyclization of the initial Schiff base and formation of oxazolidin-5-one. The low-energy decarboxylation of this intermediate makes it possible to bypass the cyclization reaction, which is in competition with thermally induced decarboxylation, and hence promote the formation of acrylamide in carbohydrate/asparagine mixtures. Although the decarboxylated Amadori compound can be formed under mild conditions, it requires elevated temperatures to cleave the carbon-nitrogen covalent bond and produce acrylamide. 相似文献
96.
Sówka Izabela Zwoździak Jerzy Zwoździak Anna Szczurek Andrzej 《Water, air, and soil pollution》2004,155(1-4):321-338
The concentrations of ambient gas-phase hydrogen peroxide were measured during the summer of 1998, 1999 and 2000. The experiments were performed in the city of Wroclaw and in the vicinity of Mount Szrenica, 1362 m a.s.l., Poland. Analysis was carried out by the chemiluminescence method. Typical mean ranges of 30 min H2O2 concentrations measured were 1.4–6.0 μg m-3 at Mount Szrenica, whereas in the urban atmosphere H2O2 concentrations were in the range of 2.7–11.7 μg m-3. In the case of the urban atmosphere, H2O2 concentrations were well correlated only with solar radiation and temperature. In the mountain air, H2O2 concentrations increased along with the increase of temperature, O3, CO and the decrease of humidity. The diurnal variation was not only caused by photochemicalprocesses. 相似文献
97.
98.
In the first study of the Protura of a big city, six representative habitat types were sampled in Vienna, Austria. Twenty-five sites between the green belt and the city centre yielded 42 known species. Abundance, species number and diversity were highest in colline deciduous forests, with a maximum of 23 syntopic species in a Quercus pubescens stand. Acerella muscorum, all of the five Acerentomon spp. and 13 further species occurred exclusively in colline deciduous forests. The mediterranean Berberentulus berberus and six other species were recorded exclusively in parks or artificial habitats, suggesting anthropogenic transport. No Protura were found in garden and arable soils. Species density in the municipal area of Vienna (415 km2) is a function of the city's biogeographic situation on the border between the Alps and the Pannonian lowland as well as its diversity of seminatural habitats, and unintentional introduction. 相似文献
99.
Magdalena Debicka Andrzej Kocowicz Jerzy Weber Elżbieta Jamroz 《Archives of Agronomy and Soil Science》2016,62(6):840-855
Phosphorus (P) sorption processes in soils contribute to important problems in agriculture: a deficiency of this plant nutrient and eutrophication in aquatic systems. Soil organic matter (SOM) plays a major role in sorption processes, but its influence on P sorption remains unclear and needs to be elucidated to improve the ability to effectively manage soil P. The aim of this research was to investigate the influence of SOM on P sorption. The study was conducted in sandy soil profiles and in topsoils before and after removal of SOM with H2O2. The results were interpreted with the Langmuir and Freundlich isotherms. Our results indicated that SOM affected P sorption in sandy soils, but that P sorption also depended on specific soil properties (e.g. values of the degree of P saturation (DPS), P sorption capacity (PSC) and pH) often related to land use. Removal of SOM decreased PSC in most of the topsoils tested; other soil properties became important in controlling P sorption. An increase in P desorption observed after SOM removal indicated that SOM was potentially that soil constituent which increased P binding and limited P leaching from these sandy soils. 相似文献
100.
European Journal of Forest Research - Garlic mustard (Alliaria petiolata (Bieb.) Cav. et Grande) is a widespread forest edge plant species in the European temperate zone and also one of the most... 相似文献