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   400篇
  免费   21篇
  国内免费   2篇
林业   41篇
农学   51篇
基础科学   9篇
  93篇
综合类   29篇
农作物   23篇
水产渔业   13篇
畜牧兽医   126篇
园艺   16篇
植物保护   22篇
  2023年   3篇
  2022年   2篇
  2021年   10篇
  2020年   9篇
  2019年   15篇
  2018年   11篇
  2017年   14篇
  2016年   20篇
  2015年   15篇
  2014年   12篇
  2013年   38篇
  2012年   21篇
  2011年   18篇
  2010年   19篇
  2009年   11篇
  2008年   15篇
  2007年   14篇
  2006年   11篇
  2005年   13篇
  2004年   7篇
  2003年   10篇
  2002年   3篇
  2001年   9篇
  2000年   5篇
  1999年   7篇
  1998年   6篇
  1997年   4篇
  1996年   4篇
  1993年   3篇
  1992年   5篇
  1991年   5篇
  1990年   13篇
  1989年   6篇
  1988年   5篇
  1987年   2篇
  1986年   3篇
  1985年   2篇
  1984年   4篇
  1983年   5篇
  1982年   2篇
  1980年   3篇
  1979年   7篇
  1978年   3篇
  1977年   2篇
  1976年   6篇
  1974年   5篇
  1971年   1篇
  1970年   3篇
  1969年   3篇
  1966年   5篇
排序方式: 共有423条查询结果,搜索用时 31 毫秒
131.
The abomasa of sheep grazing on natural pastures in the highveld of Zimbabwe were examined for Haemonchus contortus. Of 304 abomasa, 213 (70%) harboured H. contortus. The worm burden increased during the rains to reach the peak in February-March. This was followed by a decline with low worm loads throughout the dry season. The fourth stage larvae (L4) accounted for 1-7% of the total H. contortus population, except during July and August when they comprised 22 and 54% of the worm burden, respectively. It appears that the inhibition of H. contortus is not common in the commercial farming sector where sheep are treated very frequently.  相似文献   
132.
133.
134.
135.
136.
Genetic Resources and Crop Evolution - The study on Himalayan allium spices was undertaken with specific reference to commercially important taxa belonging to the genus Allium viz. A. stracheyi...  相似文献   
137.
Seed Protein Concentrates (SPC) of 6 species ofCrotalaria were extracted and the extractabilities of SPC, total N and protein N determined. SPC of high yielding species (C. juncea) was analysed for the contents of amino acids, ash, phosphorus, sugar, starch, fibre and calories, as well as forin vitro digestibility. Results indicate the promising potential ofC. juncea for SPC yield.  相似文献   
138.
Exposure of fish fingerlings (Cirrhina mrigala) and yearlings (Puntius sophore) to a concentration of 0.005 mg L?1 of linear alkyl benzene sulphonate for 24, 48, and 96 hr caused alterations in glycogen, lactic acid and sialic acid content in gill, liver, muscles and kidney. Significant decreases in the level of glycogen and elevation in the level of lactic acid demonstrated impairment of carbohydrate metabolism. Decrease in the sialic acid content suggested functional changes in membranes in toxicity.  相似文献   
139.
Genetic Resources and Crop Evolution - During survey and study of local useful plants in the West Godavari district of Andhra Pradesh a less-known species, Arivela...  相似文献   
140.
Water and temperature are critical for producing vegetable crops, especially during winter, when the availability of water is meager and temperature falls. Studies of drip irrigation and mulch were undertaken to find the effect on different growth and yield parameters in pepper (Capsicum annuum L.). The experiment was laid out in a split-plot design with four main and four subplots. Irrigation levels were placed on main plots and mulches on subplots with three replicates for each. All recorded vegetative parameters were higher with drip irrigation at 1.0 pan evaporation (Epan) and black polythene mulch. Physiological parameters such as photosynthesis rate (18.01 and 17.45 μmol m?2 s?1), transpiration rate (6.19 and 5.86 mmol H2O m?2 s?1) and chlorophyll content (27.34 and 28.39; 39.22 and 41.27 SPAD, respectively at 50 and 100 days after planting) were maximal in crops with drip irrigation at 1.0 Epan and mulched with black polythene. Soil and canopy temperature were significantly higher on flood irrigation at 1.0 Epan. Soil temperature was higher with the black polythene mulch, but canopy temperature was higher with no mulch. A higher level of drip irrigation and black polythene mulch result in early picking with higher yields compared with flood irrigation and no mulch.  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