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71.
Gross and histologic lesions of paratuberculosis were studied in water buffaloes. Small intestines and associated mesenteric lymph nodes of 405 water buffaloes were examined. Of these, 20 animals having visible changes of intestinal thickening, mucosal corrugations, and enlargement of mesenteric lymph nodes exhibited histologic alteration characteristics of mild to moderate granulomatous inflammation. The histologic lesions observed in these animals were classified into 3 grades on the basis of type of cellular infiltration, granuloma formation, and presence of acid-fast bacilli. Grade-1 lesions observed in 8 animals were marked by the presence of scattered epithelioid macrophages amid large number of lymphocytes in the intestinal villi and in the paracortical regions of the associated mesenteric lymph nodes. Another 8 animals classified under grade-2 revealed microgranulomas, infiltration with a larger number of epithelioid macrophages besides lymphocytes in the intestinal villi, and granulomas in the mesenteric lymph nodes. Grade-3 lesions observed in 4 animals were characterized by the presence of epithelioid granulomas and giant cells in the intestines and the mesenteric lymph nodes. The Ziehl-Neelsen's stained tissue sections revealed acid-fast bacilli in grade-3 and -2 animals and acid-fast granular debris in grade-1 animals. Among these 20 buffaloes, 14 (70%) were positive in the IS900 specific polymerase chain reaction and 6 (30%) were positive in the bacterial culture.  相似文献   
72.
Aquaculture International - Quantitative real-time RT-PCR (qRT-PCR) is the most sensitive and advanced method to quantify the expression of target genes of animals including fish. However, the...  相似文献   
73.
74.
Phytohemagglutinin (PHA)-induced delayed-type hypersensitivity is an immunocompetent trait considered an indicator of cell-mediated immune or T-cell responses. Divergent selection was performed to generate high and low lines for response to PHA-P. Extreme-responder birds of the F2 generation in each line were used to study possible differences in macrophage activity and the associated functional genes. To evaluate macrophage activity, nitric oxide (NO) was estimated both systemically in serum and in in vitro monocyte culture. Semi-quantitative RT-PCR was used to detect the differential mRNA expression patterns of iNOS and MIP-1beta in monocyte culture, whereas T(H)1 cytokines (IL-2 and IFN-gamma) were studied in peripheral blood mononuclear cells (PBMC) at different time intervals after lipopolysaccharide (LPS) induction. The high line showed strong systemic, as well as in vitro NO production, compared to the low line, upon stimulation with NDV and LPS, similar to early and high iNOS mRNA expression. Following the pattern of iNOS gene expression, an early strong expression of cytokines with powerful iNOS-inducing action, such as IFN-gamma and the chemokine MIP-1beta, was observed in the high line. In contrast, for response to PHA-P, low expression of IL-2 was observed in the high compared to the low line. In conclusion, the study revealed that divergent selection for response to PHA-P resulted in a divergent effect on T(H)1 cell activity, resulting in altered macrophage function in chickens. Selection, based on response to PHA-P, could lead to more resistant birds or birds with an enhanced immune response.  相似文献   
75.
A stochastic epidemic model is presented to study infection transmission dynamics, and hence epidemic severity and disease incidence, in a closed population. The aim was to understand the relative importance of various parameters that influence the dynamics of potential epidemics, particularly when the genetic mechanisms of resistance or tolerance to infection are considered. Simulations explored the effect of varying the transmission coefficient, latent period, recovery period, mortality rate, and the period of loss of immunity on overall epidemic outcomes. The critical parameters influencing the transmission of infection, and hence disease incidence, were the transmission coefficient, the latent period, and the recovery period; the period of loss of immunity had only trivial effects. Ideally, control strategies should decrease the transmission coefficient and/or increase the latent period and/or decrease the recovery period. By equating measured traits with disease transmission parameters, the model described in this paper can be used to identify which disease resistance genes or QTL will be truly effective in helping to develop disease-resistant livestock that suffer fewer epidemics and side-effects of infection. In particular, emphases should be placed on finding genes that decrease the transmission of infection, increase the latent period, or decrease the recovery period.  相似文献   
76.
When the freshwater snail Lymnaea acuminata was exposed to sub-lethal doses (2.0, 5.0, and 8.0 mg/L) of carbaryl, fecundity was significantly reduced and even stopped at higher sub-lethal doses and altered metabolic activity in the body tissue of the snail was observed. The change from aerobic to anaerobic metabolism results in lesser energy production in the body tissues of the snails, causing paralysis and finally death. This reduced fecundity and altered metabolism suggests that it would be better to avoid the use of carbaryl pesticides in the water bodies or fields adjoining the water bodies particularly in the rainy season.  相似文献   
77.
The plasma concentrations and pharmacokinetics of the fluoroquinolone antimicrobial agent pefloxacin, following the administration of a single intravenous (10 mg/kg) or oral (20 mg/kg) dose, were investigated in healthy female goats. The antimicrobial activity in plasma was measured at predetermined times after drug administration by an agar well diffusion microbiological assay, using Escherichia coli (ATCC 25922) as the test organism. Concentrations of the drug 0.25 g/ml were maintained in plasma for up to 6 and 10 h after intravenous (IV) or oral administration of pefloxacin, respectively. The concentration–time data for pefloxacin in plasma after IV or oral administration conformed to two- and one-compartment open models, respectively. Plasma pefloxacin concentrations decreased rapidly during the initial phase after IV injection, with a distribution half-life (t 1/2 ) of 0.10±0.01 h. The terminal phase had a half-life (t 1/2 ) of 1.12±0.21 h. The volume of distribution at steady state (V dss), mean residence time (MRT) and total systemic clearance (ClB) of pefloxacin were 1.08±0.09 L/kg, 1.39±0.23 h and 821±88 (ml/h)/kg, respectively. Following oral administration of pefloxacin, the maximum concentration in the plasma (C max) was 2.22±0.48 g/ml and the interval from administration until maximum concentration (t max) was 2.3±0.7 h. The absorption half-life (t 1/2 ka), mean absorption time (MAT) and elimination half-life of pefloxacin were 0.82±0.40, 4.2±1.0 and 2.91±0.50 h, respectively. The oral bioavailability of pefloxacin was 42%±5.8%. On the basis of the pharmacokinetic data, a dosage regimen of 20 mg/kg, IV at 8 h intervals or orally twice daily, is suggested for treating infections caused by drug-sensitive pathogens in goats.  相似文献   
78.
Organised by the Society of Chemical Industry on 10-15 April 1988, at the University of Nottingham. The following are summaries of posters presented at Neurotox '88, and as so presented, they are entirely the responsibility of the authors and do not reflect the views of the Editorial Board of Pesticide Science.  相似文献   
79.
The aim of this paper was to explore the effect of genetic heterogeneity in host resistance to infection on the population-level risks and outcomes of epidemics. This was done using a stochastic epidemiological model in which the model parameters were assumed to be genetically controlled traits of the host. A finite locus model was explored, with a gene controlling the transmission coefficient (i.e., host susceptibility to infection) and a gene controlling the recovery period. Both genes were simulated to have 2 alleles with underlying additive or dominance inheritance and an independent assortment of alleles. The model was parameterized for a viral pig disease (transmissible gastroenteritis), and complete homogeneous mixing among genotypes was assumed. Mean population genotype dramatically affected epidemic outcomes, and subtle effects of heterogeneity on epidemic properties were also observed. Genetic variation in the transmission coefficient led to probabilities of epidemics occurring that were slightly greater than expected, but genetic variation in the recovery rate had no such effect. Epidemics were generally less severe in genetically heterogeneous populations than expected from the constituent subpopulations. Furthermore, the genotype of the initial infected animal had a marked effect on epidemic probabilities, particularly when genetic variation was for recovery rate. The results of this model provide useful information to determine the optimum population structures and to exploit genetic variation in resistance to infection. Applications of the proposed model in genetically heterogeneous populations for identifying practical disease management strategies are also discussed.  相似文献   
80.
Both swine and equine influenza viruses were replicated in Madin-Darby canine kidney cells. Hemagglutinin and complement-fixing antigens were synthesized at 4 to 8 hours postinfection and reached maximal synthesis at 16 to 20 hours. Neuraminidase activity increased 9- to 11-fold; 50% of the total hemagglutinin antigen was made before the infective virus progeny was detected.  相似文献   
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