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111.
Red spruce (Picea rubens Sarg.) seedlings were exposed repeatedly at a field site or in a greenhouse to acidic mist containing the major sulfur and nitrogen pollutants of wet deposition in the eastern U.S.: sulfate alone, nitrate alone or with ammonium ion, and a combination of these ions. Acidities and ion concentrations ranged from below the mean to above the maximum concentration for cloudwater in the eastern U.S. Effects on elements in current-year foliage were examined after continuous or intermittent overnight exposures to mist performed over periods of 6 to 19 weeks. Principal findings from five experiments conducted over a three-year period were that acidic mist 1) increased the foliar S and/or N content when exposures were intermittent with repeated opportunities for drying of liquid on foliage; 2) decreased foliar calcium, and/or magnesium content, especially when exposures to acidic mist were continuous rather than intermittent; and 3) gave inconsistent results for foliar iron and aluminum probably because of deposition of soil particles and contamination with metals from the mist delivery system. These results indicate that long-duration exposures to cloudwater with pH below 3 may alter foliar nutrient composition and change relationships between N, S, Ca, and Mg, with potential consequences for growth and resistance to natural stress factors.  相似文献   
112.
Abstract –  Habitat suitability criteria (HSC) for depth, mean velocity, nose velocity, substrate, embeddedness, and cover were developed for brown trout ≥170 mm ( Salmo trutta Linnaeus) on the West Branch Farmington River, CT, USA. Microhabitat data was collected by underwater observation using an equal effort habitat sampling design; HSC were constructed using nonparametric tolerance limits. Transferability of previously published HSC to the West Branch Farmington River was poor; only 1 of 13 HSC tested was considered transferable. The HSC developed for the West Branch Farmington River were tested for transferability to the East Branch Westfield River, Massachusetts. First, a composite suitability index (SI) score was calculated using the source HSC for each occupied and unoccupied location in the Westfield River. Then, χ 2-tests were used to determine if optimal or suitable locations were occupied in greater proportion than usable or unsuitable locations. Composite SI scores based on total depth, mean velocity, and cover were not transferable, but composite SI scores based only on total depth and mean velocity were. A multivariate profile analysis was also used to test for transferability. In each test, only total depth, fish depth, and mean velocity HSC were successfully transferred. Transferability of depth and velocity HSC between rivers shows promise for applications to similar systems where brown trout occur.  相似文献   
113.
Harvesting stem biomass from the forest inevitably involves exporting nutrients from the ecosystem. The amount exported is increased when the logging residues are also removed for use as fuel. Recycling of the resulting wood ash has been advocated as a measure to compensate for the nutrient losses and to sustain future forest production. The physical formulation of the wood ash may have an important influence on its effects on soil properties. In this paper, we report effects of two different types of wood ash (one self-hardened and crushed, the other pelleted), with differences in solubility, on soil chemistry in the humus layer and upper 15 cm of the mineral soil, at two coniferous sites in south-central Sweden, 5 yr after their application. The crushed ash was applied at three doses (3, 6 and 9 ton ha–1), while the pelleted ash was applied at only one dose (3 ton ha–1). At both sites the soil was podzolized. The two sites differed with respect to soil conditions, despite being situated only a few kilometers apart. The application of wood ash increased both soil pH and base-cation content in the humus layer at both sites. In the mineral soil, the effects were less pronounced. Treatment effects on soil chemistry did not differ between the two ash formulations. The retention (i.e. the extractable amount of nutrients found in the soil that could be attributed to the ash application) of nutrients varied strongly between the two sites, and K retention (ca. 10%) was generally lower than that of Ca and Mg.  相似文献   
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Two flocks of pure bred Dorper lambs were managed separately according to sex (283 ewe lambs and 212 ram lambs) in southern Western Australia. Faecal sample collection, weighing and body condition assessments were performed for each lamb on 2 occasions, specifically pre-weaning (approximately 14 weeks of age) and post-weaning (approximately 9 months of age). Body condition score (BCS) was assessed using a scale of 1 (very thin, emaciated) to 5 (excessively fat). Faecal worm egg counts (WECs) were measured using a modified McMaster technique and larval cultures were performed to identify trichostrongylid nematode genera present. Eye muscle and c-site fat depths were measured using ultrasound at post-weaning. Lambs received an abamectin anthelmintic treatment at weaning (18 weeks of age). Worm egg count data was assessed for normality of data distribution and homogeneity of variance. This data was transformed using log(10)(WEC+25) to stabilise variances between groups prior to statistical analyses and general linear models were used to assess relationships between WEC and productivity measures. Mean WECs were 564 eggs per gram of faeces (EPG) and 514 EPG at pre- and post-weaning in the ewe flock and 552 EPG and 480 EPG at pre- and post-weaning in the ram flock. Teladorsagia (Ostertagia) circumcincta, Trichostrongylus spp. and Oesophagostomum spp. larvae were identified. No lambs with WEC<500 EPG pre-weaning had WEC>1000 EPG post-weaning. Ewe and ram lambs with WEC>1000 EPG at pre-weaning were 42 (12-145 95% CI) and 37 (9-153) times more likely to have WEC>1000 EPG at post-weaning than lambs with WEC 501-1000 EPG at pre-weaning. There were no significant relationships between WEC and live weight in the ram flock, while relationships between WEC and live weight were inconsistent in the ewe lamb flock. There was no relationship between WEC and eye muscle or c-site fat depth. Significant negative relationships between WEC and BCS were identified at pre- and post-weaning for both flocks. Lambs with WEC<500 EPG had 0.19-0.61 higher mean BCS than lambs with WEC>1000 EPG at pre- and post-weaning. In conclusion, high WEC was associated with lower body condition in Dorper lambs, however the relationship between WEC and live weight was inconsistent and there was no effect on eye muscle depth.  相似文献   
117.
Most global climate change models predict serious ecological and social problems. In Japan, biologists have found climate change is affecting species and ecosystems, including the earlier flowering time of cherry trees which are an important cultural symbol in Japan. Cherry blossom festivals are also important to local economies. This study explored the perceptions of Japanese residents regarding climate change impacts on culturally significant events such as flower timing of cherry trees. We conducted interviews of stakeholders of three cherry blossom festivals, including sixteen organizers of festivals and 26 managers of festival-dependent businesses, to understand their awareness, attitudes and behaviors toward global climate change and impacts on cherry blossom festivals. Most organizers of the festival in Kakunodate were concerned about global warming and its impact on cherry blossom times while organizers of festivals in Nakano and Komoro felt it was unimportant if flower timing affected the festival schedule. Most (92%) managers of festival-dependent businesses mentioned that global warming is occurring and affecting the flower timing of cherry trees, but there were diverse perceptions of global warming impacts on their business. Managers more dependent on income from cherry blossom festivals indicated greater concern for the effects of climate change.  相似文献   
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Enzyme-linked immunosorbent assay (ELISA) test kits have been used widely to diagnose FeLV infection. Several companies have licensed such kits, but because these test kits are designed somewhat differently, a demonstration of their relative merits was needed. Differences in the sensitivity and specificity of 7 commercial test kits were determined by testing sera that induce false-negative (limiting dilution of FeLV group specific antigen, p27), and false-positive (cat anti-mouse antibody) test results. Among the panels of sera used in this study, significant differences in test kit sensitivity were not observed, but differences in specificity were identified. An interim report of these studies, supplied to the manufacturers, prompted changes in some of the kits, resulting in improved specificities. Generally, FeLV test kits are now more efficient in accurately detecting p27 in blood, serum, or plasma of cats. Nevertheless, some kits still lack specificity attributable to reagents supplied by the manufacturer.  相似文献   
120.
Reptiles     
Basic techniques that will allow the clinician to properly evaluate the ill reptile are discussed. How to take a complete history and a systematic approach to physical examination are emphasized. Techniques for collection of samples for clinical evaluation and selection of drugs for treating ill reptiles are reviewed briefly.  相似文献   
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