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51.
52.
Previously, we have reported that the injection of an expression vector containing Herpes simplex virus (HSV) Glycoprotein D-1 (gD-1) generated a significant antibody response in mice and protected them against HSV lethal challenge. We tested its potential to induce antibody and cell mediated immune responses in latently infected mice. Positive control group (KOS) and HSV gD-1 vaccinated mice demonstrated protection against a lethal ocularly challenge of 10(5.5) plaque-forming units (pfu)/eye of wild HSV-1 versus negative control groups. For neutralizing antibody titers, delayed-type hypersensitivity (DTH), lymphocyte proliferation responses, clinical evaluation and survival following lethal challenge, no considerable difference was observed between mice vaccinated with DNA plasmid and those vaccinated with KOS. KOS-vaccinated mice demonstrated the ability to completely prevent latency whereas DNA vaccinated group showed some degree of protection and displayed less latency than negative control groups and had considerably high levels of IFN-gamma and strong CTL responses versus negative control groups. It can be concluded that although immunization with the DNA vaccine is more effective in both protecting mice and induction of immune response, however it could not completely block the latent infection in sensory nerves.  相似文献   
53.
Forage sorghum yield and water use efficiency under variable irrigation   总被引:1,自引:0,他引:1  
The response of forage sorghum [Sorghum bicolor (L.) Moench] to three irrigation treatments in a semiarid environment was studied in the field for two seasons. Treatments were light frequent, moderate less frequent, and heavy infrequent irrigation, where irriga-tion water at 8 mm day–1 was delivered every 7, 10, and 13 days, respectively. These irrigation regimes meant heavier water inputs with increasing irrigation frequency. Plant heights and leaf area indices of forage sorghum were higher in the frequently watered plots than in plots where irrigation water was delivered less frequently. Averaged over the two seasons, maximum dry matter (DM) yields were 16.3, 11.8, and 10.5 tonnes ha–1 for frequent, intermediate, and infrequent irrigation regimes, respectively. Light, frequent irrigation resulted in a significantly higher water use efficiency (WUE) compared to the other two regimes, thus increasing the return from irrigation. These results suggest that in such semiarid environments, DM yields and WUE of forage sorghum could be increased by combining light irrigation with a short interval. Received: 6 February 1997  相似文献   
54.
The antibacterial activities of essential oils and herbal extracts have been demonstrated against a range of bacterial species. In this study, the antibacterial effects of a new combination of essential oils from the herbs Thymus vulgaris, Salvia officinalis, Eucalyptus globulus and Mentha piperita were assayed against common bacterial isolates (Staphylococcus aureus, Escherichia coli and Pseudomonas aeroginosa) and fifteen novel marine bacteria isolates. The sensitivity of different isolates to antibacterial activity of the essential oils was determined using well diffusion assays. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were quantified by micro dilution assays. The data demonstrate that the combination of essential oils had potent antibacterial effects and marine bacteria were more sensitive to growth inhibition (P < 0.05). MIC rates were 0.77–6.18 mg/ml, and MBC rates were 1.67–12.30 mg/ml. This indicates that the combined essential oils (CEO) can be a new source of antibacterial agents for use in marine aquaculture.  相似文献   
55.
Today, due to the rapid spoilage of fish, the use of natural preservatives is a priority over those of synthetic varieties. Also, the natural antimicrobial effects of essential oils can help to increase shelf life. There are very few studies concerning the use of essential oils in this regard. In the present study, the antibacterial effect of chitosan coated with Heracleum persicum oil was investigated on the quality of rainbow trout. The control and the coated fish samples were analyzed periodically by generalized estimating equation (GEE) for total viable count (TVC), psychrophilic bacteria, total volatile base nitrogen (TVB-N), polyunsaturated fatty acids (PUFA), texture, taste, odor, and overall acceptance parameters. The results showed that by increasing the amount of chitosan, TVC, psychrophilic bacteria, and TVB-N decreased while PUFA, texture, taste, odor, and overall acceptance parameters increased.  相似文献   
56.
The main aim of the present study was to assess the effects of chronic high stocking density on liver proteome of rainbow trout. Rainbow trout juveniles (42.6 ± 2.3 g average body weight) were randomly distributed into six tanks at two stocking densities (low stocking density (LD) = 20 kg m?3 and high stocking density (HD) = 80 kg m?3). Both treatments were performed in triplicate tanks for a period of 60 days. High stocking density caused a reduction in the growth performance compared with LD fish. Lysozyme activity increased with stocking density, while serum complement activity presented the opposite pattern. Serum cortisol and total protein levels did not show significant differences (P > 0.05) between experimental groups. The fish reared at high stocking density showed significantly lower osmolality and globulin values but higher albumin level. The HD group had significantly higher activities of catalase, glutathione peroxidase and superoxide dismutase, and malondialdehyde content in the liver when compared to the LD group. Comparative proteomics was used to determine the proteomic responses in livers of rainbow trout reared at high stocking density for 60 days. Out of nine protein spots showing altered abundance (>1.5-folds, P < 0.05), eight spots were successfully identified. Two proteins including apolipoprotein A-I-2 precursor and mitochondrial stress-70 protein were found to increase in HD group. The spots found to decrease in the HD group were identified as follows: 2-peptidylprolyl isomerase A, two isoforms of glyceraldehydes-3-phosphate dehydrogenase, an unnamed protein product similar to fructose-bisphosphate aldolase, 78 kDa glucose-regulated protein, and serum albumin 1 protein.  相似文献   
57.
Knowledge of crop production in suboptimal environmental conditions not only helps to sustain crop production but also aids in the design of low-input systems. The objective of this study was to evaluate the effects of water stress imposed at low-sensitive growth stages (vegetative, reproductive, and both vegetative and reproductive) and level of nitrogen (N) supply (100 and 200 kg ha−1) on the physiological and agronomic characteristics of two hybrids of maize (Zea mays L.). A two-site field experiment was carried out using a randomized complete block design with three replications and a split-factorial arrangement. A water deficit (WD) was induced by withholding irrigation at different stages of crop development. The results showed that proline content increased and the relative water content, leaf greenness, 100-kernel weight and grain yield decreased under conditions of WD. The highest IWUE was obtained when maize endured WD at vegetative stage at two sites. The limited irrigation imposed on maize during reproductive stage resulted in more yield reduction than that during vegetative stage, compared with fully irrigated treatment. The 100-kernel weight was the most sensitive yield component to determine the yield variation in maize plant when the WD treatments were imposed in low-sensitive growth stages. The results of the statistical regression analysis showed liner relationships between RGR during a period bracketing the V8 or R3 stages and 100-kernel weight in all the WD treatments. The increase of N supply improved yield and IWUE when maize plant endured once irrigation shortage at vegetative stage. But, the performance of high N fertilizer reduced and eliminated when water deficit imposed once at reproductive stage and twice at vegetative and reproductive stages, respectively. Furthermore, the response of T.C647 hybrid to increase of N supply was stronger than S.C647 hybrid.  相似文献   
58.
Yield and water productivity of potatoes grown in 4.32 m2 lysimeters were measured in coarse sand, loamy sand, and sandy loam and imposed to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments received 65% of FI after tuber bulking and lasted for 6 weeks until final harvest. Analysis across the soil textures showed that fresh yields were not significant between the irrigation treatments. However, the same analysis across the irrigation treatments revealed that the effect of soil texture was significant on the fresh yield and loamy sand produced significantly higher fresh yield than the other two soils, probably because of higher leaf area index, higher photosynthesis rates, and “stay-green” effect late in the growing season. More analysis showed that there was a significant interaction between the irrigation treatments and soil textures that the highest fresh yield was obtained under FI in loamy sand. Furthermore, analysis across the soil textures showed that water productivities, WP (kg ha−1 fresh tuber yield mm−1 ET) were not significantly different between the irrigation treatments. However, across the irrigation treatments, the soil textures were significantly different. This showed that the interaction between irrigation treatments and soil textures was significant that the highest significant WP was obtained under DI in sandy loam. While PRD and DI treatments increased WP by, respectively, 11 and 5% in coarse sand and 28 and 36% in sandy loam relative to FI, they decreased WP in loamy sand by 15 and 13%. The reduced WP in loamy sand was due to nearly 28% fresh tuber yield loss in PRD and DI relative to FI even though ET was reduced by 9 and 11% in these irrigation treatments. This study showed that different soils will affect water-saving irrigation strategies that are worth knowing for suitable agricultural water management. So, under non-limited water resources conditions, loamy sand produces the highest yield under full irrigation but water-saving irrigations (PRD and DI) are not recommended due to considerable loss (28%) in yield. However, under restricted water resources, it is recommended to apply water-saving irrigations in sandy loam and coarse sand to achieve the highest water productivity.  相似文献   
59.
The spermatozoa of oviparous fish, such as feral carp (Cyprinus carpio), are immotile in the presence of semen plasma or isotonic solutions, and to obtain good motility, they must be diluted with suitable medium. The objective of this study was to identify the best activating solution for feral carp sperm. Sperm motilities were compared in the new activating solution (a): (50 mM NaCl, 30 mM KCl, 30 mM Tris, pH = 8.5) and activating solution (b): (50 mM NaCl, 40 mM KCl, 30 mM Tris, pH = 8.5) based on effect of pH with everyone of Na+ and K+ ions versus four other activating solutions Billard’s saline solution, Poupard’s saline solution, distilled water and hatchery water that is routinely used for extending carp semen. Our results showed that maximum total motility period and percentage of motile sperm were seen in selected saline solution (a). The present study describes an activating solution that prolongs feral carp sperm motility.  相似文献   
60.
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