首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   36篇
  免费   4篇
林业   3篇
农学   5篇
  16篇
综合类   1篇
农作物   2篇
水产渔业   1篇
畜牧兽医   9篇
园艺   2篇
植物保护   1篇
  2022年   3篇
  2021年   1篇
  2020年   1篇
  2018年   1篇
  2015年   2篇
  2013年   4篇
  2012年   2篇
  2011年   1篇
  2010年   5篇
  2006年   4篇
  2005年   2篇
  2004年   4篇
  2002年   2篇
  1990年   1篇
  1987年   1篇
  1985年   2篇
  1983年   1篇
  1979年   3篇
排序方式: 共有40条查询结果,搜索用时 15 毫秒
11.
Experimental Hg poisoning in the fish, Barbus conchonius led to marked hematological anomalies. Acute exposure to 181 μg L?1 mercuric chloride (96 h LC50) led to erythrocytic anomalies including vacuolation, nuclear deterioration, microcytosis and collapsed cytoplasmic membranes. In addition, there was significant thrombocytosis and neutropenia together with a slight reduction in lymphocyte count. Chronic exposure to 36 and 60 μg L?1 mercuric chloride led to poikilocytosis, hypochromia, fragmentation and nuclear displacement in erythrocytes. The large lymphocytes revealed vacuolation, cellular and nuclear hypertrophy and cytoplasmic outgrowths. Thrombocytosis, lymphocytosis, neutropenia and mild basophilia were manifested in fish subjected to chronic poisoning.  相似文献   
12.
The rice–wheat rotation covering 13.5 million ha in the Indo-Gangetic Plains is vital for food security. Its sustainability is at risk as the current production practices are inadequate resulting in high cost of cultivation and inefficient use of inputs (i.e. water, labor and energy). In a field study, we evaluated resource conserving and cost-saving alternative tillage and crop establishment options with an aim to improve system productivity and efficiency. Treatments included transplanting and direct-seeding of rice after reduced and no-tillage, followed by wheat after no-tillage. Conventional-tilled (puddled) transplanted rice followed by conventional-tilled wheat was included as a current practice. Rice yields of transplanted rice were similar irrespective of tillage/puddling. However, both dry and wet direct-seeded rice yielded 0.45–0.61 Mg ha−1 lower than puddled transplanted rice. Wheat yield after no-tillage was either higher or equivalent to conventional practice. Wheat provided more economic return (US $35 ha−1) than rice. No-till wheat was 6% more profitable than the conventional practice (T1). Rice transplanting with or without puddling had similar water application but dry direct-seeded rice had 10–12% lower and wet direct-seeded rice 20–24% higher. Machine labor without tillage was lower by maximum of 51 and 43% in rice and wheat, respectively. Similarly, human labor was also 9–16% lower in no-till rice compared to other practices. Two years results consistently showed $35 more net income when rice was transplanted without puddling than that of conventional practice. Direct-seeded/un-tilled rice had variable response in 2 years; US $16 more in year 1 and similar in year 2 to the puddled transplanted rice. Direct-seeded or transplanted rice after no-tillage can be more efficient and profitable alternatives to current practice (puddled transplanted rice), however, require further refinement in areas of cultivar development for no-till direct-seeding condition, nutrient, water and weed management to harness maximal potential.  相似文献   
13.
14.
Echinococcosis is an important medical, veterinary and economic concern in India. Ten cysts were randomly selected from each intermediate host species (cattle, buffalo, sheep, goat and pigs). Either the germinal layer (sterile cysts) or protoscoleces (fertile cysts) were collected for molecular characterization. A 434 base pair fragment of the mitochondrial cytochrome oxidase-1 gene was amplified using PCR from each isolate. Ten representative samples (2 from each intermediate host species) were sequenced in both the directions from which readable sequences were obtained from nine for phylogenetic analysis (NCBI, Blast). Phylogenetic analysis of cytochrome oxidase I gene revealed that seven (77.7%) isolates, from cattle (2), pigs (2), buffaloes (1) and goat (2) were clustered with the Indian Buffalo (G3) strain of Echinococcus granulosus, while two (22.2%) isolates from sheep were clustered with the sheep strain (G1) of E. granulosus. Phylogenetic analysis of the cytochrome oxidase-1 gene revealed that the buffalo strain (G3) and common sheep strain (G1) are cycling among livestock in north India and that these strains are highly adapted to cattle, buffalo, sheep, goats and pigs.  相似文献   
15.
16.
Teratomas are neoplasms of embryonal origin in domestic animals and are generally associated with reproductive organs. We report a case of teratoma involving the right kidney in a young llama that presented clinically with signs of mild colic and constipation.  相似文献   
17.
Fourier transform infrared (FTIR) spectroscopy with microattenuated total reflectance (mATR) sampling accessory and chemometrics (partial least squares and principal component regression) was used for the simultaneous determination of saccharides such as fructose, glucose, sucrose, and maltose in honey. Two calibration models were developed. The first model used a set of 42 standard mixtures of fructose, glucose, sucrose, and maltose prepared over the range of concentrations normally present in honey, whereas the second model used a set of 45 honey samples from various floral and regional sources. The developed models were validated with different data sets and verified by high-performance liquid chromatography (HPLC) measurements. The R (2) values between the FTIR-mATR predicted and HPLC results of the different sugars were between 0.971 and 0.993, demonstrating the predictive ability and accuracy of the procedure.  相似文献   
18.
A critical handicap to tropical biodiversity conservation efforts in agroecosystems is the unknowns regarding the influence of landscape-scale factors on the persistence of species. To address these uncertainties, we explored two essential landscape-scale questions, within India’s biologically-rich Western Ghats, examining two nearby human-dominated landscapes that dramatically differed in their pattern of land cover. First, how does the proximity of intact forest patches affect bird community composition within agricultural landscapes? Second, can simple remote sensing-derived measures (brightness, wetness, and NDVI) be used to estimate native bird species composition within those landscapes? In both landscapes, as distance to intact forest decreased, the similarity in bird community composition between agricultural areas and intact forest increased. This suggests that the retention of tropical forest bird communities within human-dominated landscapes critically depends on the maintenance of nearby intact forest. In an answer to the second question, the remote sensing measures correlated with forest-affiliated avian species richness in only one of the two landscapes, reflecting an ecological difference between the two in the response of forest bird species to local agricultural conditions. In the landscape where a correlation was found, there was high variation in vegetative structure, which strongly impacted both the remote sensing measures and forest bird species richness. In the other landscape, forest species richness strongly correlated with changes in tree species composition in the agriculture, a factor that could not be detected by the remote sensing metrics. In order to successfully conserve biodiversity in tropical agricultural landscapes, our findings show that it is essential to conserve intact forest within those landscapes and to understand the effect of local agricultural practices on species.  相似文献   
19.
20.
Exposure of a freshwater cyprinid (Puntius conchonius) to 2.142 and 4.784 ppm of carbaryl and dimethoate, respectively, for 24 hr, seriously affected carbohydrate and cholesterol metabolism. Significant hyperglycemia and glycogenolysis in liver, brain, and heart were manifested in the treated fish. Hypercholesterolemia and rise in liver cholesterol also occurred. Long-term exposure, 15–30 days, to chronically sublethal concentrations, 0.194 and 0.306 ppm carbaryl and 0.434 and 0.683 ppm dimethoate, elicited hypoglycemia and depletion of liver glycogen, together with enhanced glycogenesis in the heart. The glycogen level in brain fell in response to carbaryl exposure in contrast to a significant elevation caused by dimethoate. Reduction in blood and liver cholesterol at 15 days was followed by an increase at 30 days.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号