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21.
Elisabeth Lindahl Nosirjon Sattorov Sofia Boqvist Izzatullo Sattori Ulf Magnusson 《Tropical animal health and production》2014,46(3):563-569
In this cross-sectional study, we assessed and mapped the seroprevalence of brucellosis in small-scale dairy farming in an urban and peri-urban area of Tajikistan and investigated factors associated with seropositivity. As urban and peri-urban farming is both an opportunity to improve the livelihood for small-scale farmers and a potential public health hazard, studies are warranted to reveal possible peculiarities in the epidemiology of brucellosis in this type of dairy farming. In total, 904 cows of breeding age belonging to 443 herds in 32 villages were serologically tested with indirect enzyme-linked immunosorbent assay (ELISA) and positive samples confirmed with competitive ELISA. Two logistic regression models were used to investigate an association between seropositivity and risk factors at herd and individual level. The herd and individual seroprevalences were 4.1 and 2.0 %, respectively. Herds with a history of abortions were found to be associated with seropositivity [odds ratio (OR)?=?5.3; 95 % confidence interval (CI), 1.3–21.3]. Large herds with more than eight cattle were more likely to be seropositive compared to smaller herds with one to two cattle (OR?=?13.9; 95 % CI, 1.6–119). The number of calves produced per cow (indicating age) was found to be associated with seropositivity. Younger cows with one to two produced calves were less likely to be seropositive compared to older cows with more than six produced calves (OR?=?0.24; 95 % CI, 0.06–1.0). Neither introduction of new cattle to the herd nor communal grazing was associated with seropositivity. This study shows that infection with Brucella (1) is present in small-scale urban and peri-urban dairy farming in Tajikistan and (2) has significant negative effects on reproductive performance in this farming system and (3) that some previously known risk factors for seropositivity in rural farming system were absent here. 相似文献
22.
23.
- 1. The topmouth gudgeon Pseudorasbora parva Schlegel, 1842, a south-east asian cyprinid, was introduced accidentally in the Danube Delta in Romania in the 1960s and has now achieved a pan-Danubian distribution. P. parva has been introduced into other countries, such as Greece, usually inadvertently included with other species imported for fish farming. In 1984–85, during a study of the fish populations of Lake Mikri Prespa (north-west Greece), several topmouth gudgeon were caught. Our aim was to study the changes in the population size of P. parva over nearly 10 years, to study its life history traits and to assess its potential impacts on native fish species.
- 2. The catch per unit effort (CPUE) in spring increased significantly between 1984 and 1992. We found evidence that P. parva has established a breeding population in the lake. P. parva combines many characteristics likely to favour a successful colonization (resistance to harsh climatic conditions, early sexual maturity, extended breeding season, broad dietary spectrum). Growth in Lake Prespa, where the oldest individuals captured were 3 years old, is very similar to that observed within its native range.
- 3. There is evidence for dietary overlap between P. parva and three endemic species: Paraphoxinus epiroticus prespensis, Cobitis meridionalis and Alburnoides bipunctatus ohridanus. No decline in the populations of these three species has yet been demonstrated. Other possible impacts are discussed. The successful colonization by P. parva was certainly favoured by the absence of a true piscivorous fish in the lake and by the isolation and high level of endemism of fish communities.
- 4. The conservation of the many endemic species in the lake should be a priority and the introduction of exotic species should be banned.
24.
This study is an attempt to go further in the comprehension of the effects of heavy fuel oil in the context of an accidental
oil spill at sea. It focuses on the link between morphological and functional impacts of realistic doses of the dissolved
fraction of a heavy fuel oil on fish gills. Juvenile turbot, Scophthalmus maximus were exposed to the dissolved fraction of a heavy fuel oil for 5 days and then placed 30 days in clean sea water for recovery.
During the contamination period, the concentration of the 16 US EPA priority poly-aromatic hydrocarbons showed small variations
around a mean value of 321.0 ± 9.1 ng l−1 (mean ± SEM). The contamination induced a 64% increase in hepatic cytochrome P 450 1A (Western blot analysis). Osmolality,
[Na+] and [Cl−] rapidly and significantly increased (by 14, 23 and 28% respectively) and slowly decreased to normal levels during the recovery
period. At the same time, branchial histology showed decreases in the number of mucocytes (by 30%) and of chloride cells (by
95%) in the interlamellar epithelium. Therefore, it is suggested that the osmotic imbalance observed after the 5 days of exposure
to the dissolved fraction of the heavy fuel oil is the consequence of the structural alteration of the gills i.e, the strong
reduction of ionocyte numbers. 相似文献
25.
Vishwanath Patil Torsten Källqvist Elisabeth Olsen Gjermund Vogt Hans R. Gislerød 《Aquaculture International》2007,15(1):1-9
Twelve algal strains representing the classes Cyanophyceae, Prymnesiophyceae, Bacillariophyceae, Rhodophyceae, Cryptophyceae,
Chlorophyceae, Xantophyceae and Eustigmatophyceae were selected mainly from the culture collection of the Norwegian Institute
for Water Research (NIVA). The algae were grown as continuous cultures in a 1.8 l. reactor, internally illuminated with an
11 W fluorescent tube. The retention time was adjusted in the range 2–4 days to fit the growth rate of the algae. The growth
responses and fatty acid composition were analysed. The maximum production rate was obtained with Pseudokirchneriella subcapitata (0.63 g 1−1 day−1) and the lowest with Porphyridium cruentum 0.13 g 1−1 day−1. Arachidonic acid (AA) and eicosapentaenoic acid (EPA) were the dominating polyunsaturated fatty acids (PUFAs) in P. cruentum, while only EPA accumulated in Phaeodactylum tricornutum. Docosahexaenoic acid (DHA) was the major PUFA in Isochrysis galbana, while Pavlova sp. had both EPA and DHA. This is the first report on the fatty acid profiles of Nannochloropsis oceanica, Chroococcus sp., Synechococcus sp. and Tribonema sp. 相似文献
26.
Different thermal treatments or processes (combustion, welding, thermowood) of several wood species were examined and compared. Each procedure resulted in different temperature loads on wood. The changes of lignin after thermal treatments were determined by different suitable methods, both wet chemical and instrumental analyses.The characterisation of the wood meals by means of FTIR spectroscopy has shown that changes of the aromatic skeletal vibrations occur, which indicate condensation reactions of lignin. The variations within the FTIR spectra of hardwood were more evident than those of softwood.The decomposition of lignin has also been proven in the acetone extracts of “thermowood”, which contained a lignan, identified by GC/MS.Moreover, the thioacidolysis showed the decrease of monomeric degradation products in all thermal treated samples. This is due to the cleavage of structural units bound by arylgycerol-β-ether linkages.However, it can be assumed that in addition to the degradation of specified types of bonds also condensation reactions have occurred and these products were not detectable by means of GC/MS. This conclusion would also support the above-mentioned results of FTIR spectroscopy. 相似文献
27.
OBJECTIVES: To investigate the tracking of sugar-sweetened, carbonated soft drinks intake from age 15 to 33 years and the association between this intake and lifestyle factors and body weight. DESIGN: A longitudinal study with 18-20 years of follow-up. Data about diet, physical activity, smoking and dieting were collected in 1981/1979, 1991 and 1999. Body weight and height were measured in 1981/1979 and self-reported in 1999. SETTING: Oslo, Norway. SUBJECTS: Four hundred and twenty-two men and women. RESULTS: Tracking of soft drinks intake from adolescence into early adulthood (age 25 years) and from early adulthood into later adulthood (33 years) was moderate to high, while tracking from adolescence into later adulthood was low. Comparing those reporting a high intake of soft drinks in both 1991 and 1999 with those reporting a low intake at both times, male long-term high consumers were more likely to smoke (48 vs. 21%, P=0.002) and reported higher intakes of energy (12.2 vs. 10.2 MJ day(-1), P=0.005) and sugar (142 vs. 50 g day(-1), P<0.001) in 1999 than did long-term low consumers. Women high consumers were less likely to be physically active (14 vs. 42%, P=0.03) and had higher sugar intake (87 vs. 41 g day(-1), P<0.001) in 1999 than did women low consumers. There were no differences in body mass index, overweight or obesity in 1999 between long-term high and low consumers. CONCLUSION: In this study, stability of soft drinks intake from age 15 to 25 years and from age 25 to 33 years was moderate to high, while from age 15 to 33 years it was low. Soft drinks intake from age 25 to 33 years was associated with smoking and physical inactivity, but not with body weight. 相似文献
28.
This paper reports a 3D-QSAR study using Catalyst software to explain the nature of interactions between flavor compounds and beta-lactoglobulin. A set of 35 compounds, for which dissociation constants were previously determined by affinity chromatography, was chosen. The set was divided into three subsets. An automated hypothesis generation, using HypoGen software, produced a model that made a valuable estimation of affinity and provided an explanation for the lack of correlation previously observed between the hydrophobicity of terpenes and the affinity for the protein. On the basis of these results, it appears that aroma binding to beta-lactoglobulin is caused by both hydrophobic interactions and hydrogen bonding, which plays a critical role. Catalyst appears to be a reliable tool for the application of 3D-QSAR study in aroma research. 相似文献
29.
Gebauer R Volarík D Urban J Børja I Nagy NE Eldhuset TD Krokene P 《Tree physiology》2011,31(10):1103-1113
Conifers and other trees are constantly adapting to changes in light conditions, water/nutrient supply and temperatures by physiological and morphological modifications of their foliage. However, the relationship between physiological processes and anatomical characteristics of foliage has been little explored in trees. In this study we evaluated needle structure and function in Norway spruce families exposed to different light conditions and transpiration regimes. We compared needle characteristics of sun-exposed and shaded current-year needles in a control plot and a thinned plot with 50% reduction in stand density. Whole-tree transpiration rates remained similar across plots, but increased transpiration of lower branches after thinning implies that sun-exposed needles in the thinned plot were subjected to higher water stress than sun-exposed needles in the control plot. In general, morphological and anatomical needle parameters increased with increasing tree height and light intensity. Needle width, needle cross-section area, needle stele area and needle flatness (the ratio of needle thickness to needle width) differed most between the upper and lower canopy. The parameters that were most sensitive to the altered needle water status of the upper canopy after thinning were needle thickness, needle flatness and percentage of stele area in needle area. These results show that studies comparing needle structure or function between tree species should consider not only tree height and light gradients, but also needle water status. Unaccounted for differences in needle water status may have contributed to the variable relationship between needle structure and irradiance that has been observed among conifers. 相似文献
30.
Head JW Campbell DB Elachi C Guest JE McKenzie DP Saunders RS Schaber GG Schubert G 《Science (New York, N.Y.)》1991,252(5003):276-288
Magellan images confirm that volcanism is widespread and has been fimdamentally important in the formation and evolution of the crust of Venus. High-resolution imaging data reveal evidence for intrusion (dike formation and cryptodomes) and extrusion (a wide range of lava flows). Also observed are thousands of small shield volcanoes, larger edifices up to several hundred kilometers in diameter, massive outpourings of lavas, and local pyroclastic deposits. Although most features are consistent with basaltic compositions, a number of large pancake-like domes are morphologically similar to rhyolite-dacite domes on Earth. Flows and sinuous channels with lengths of many hundreds of kilometers suggest that extremely high effusion rates or very fluid magmas (perhaps komatiites) may be present. Volcanism is evident in various tectonic settings (coronae, linear extensional and compressional zones, mountain belts, upland rises, highland plateaus, and tesserae). Volcanic resurfacing rates appear to be low (less than 2 Km(3)/yr) but the significance of dike formation and intrusions, and the mode of crustal formation and loss remain to be established. 相似文献