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   713篇
  免费   45篇
林业   27篇
农学   11篇
基础科学   2篇
  47篇
综合类   165篇
农作物   13篇
水产渔业   65篇
畜牧兽医   391篇
园艺   11篇
植物保护   26篇
  2020年   8篇
  2019年   13篇
  2018年   14篇
  2016年   6篇
  2015年   8篇
  2013年   24篇
  2012年   22篇
  2011年   17篇
  2010年   21篇
  2009年   16篇
  2008年   19篇
  2007年   26篇
  2006年   17篇
  2005年   21篇
  2004年   13篇
  2003年   15篇
  2002年   12篇
  2001年   15篇
  2000年   22篇
  1999年   21篇
  1998年   23篇
  1997年   19篇
  1996年   16篇
  1995年   14篇
  1994年   9篇
  1993年   8篇
  1992年   10篇
  1991年   22篇
  1990年   25篇
  1989年   19篇
  1988年   7篇
  1987年   22篇
  1986年   14篇
  1985年   10篇
  1984年   9篇
  1983年   7篇
  1982年   10篇
  1981年   7篇
  1980年   8篇
  1979年   11篇
  1978年   8篇
  1977年   6篇
  1976年   9篇
  1975年   9篇
  1974年   7篇
  1971年   10篇
  1970年   7篇
  1969年   6篇
  1967年   11篇
  1966年   6篇
排序方式: 共有758条查询结果,搜索用时 15 毫秒
1.
2.
Book reviews     
The T.M.E. System of Feed Evaluation. I.R. Sibbald, Animal Research Centre Contribution 83‐1, Animal Research Centre, Ottawa, Ontario, Canada.

Physiology and Behaviour of the Pigeon, edited by M. Abs. 1983. 360 pages, illustrated. London, Academic Press Ltd. Price £34.00. ISBN 0 12 042950 0.  相似文献   

3.
4.
5.
1. The amino acid composition of the whole body protein of 28‐ and 56‐d‐old turkeys is reported.

2. There were some differences between the two ages; these could largely be reconciled by considering the likely differences in the proportion of feather protein.

3. The results were compared with similar values for the chicken and goose; overall there is a striking similarity, both in absolute concentrations and relative proportions of amino acids.  相似文献   

6.
The systemic fungicides furalaxyl, metalaxyl and ofurace,
  • 1 Ofurace is the proposed BSI and ISO common name for α-(2-chloro-N-2,6-xylylacetamido)-γ-butyrolactone.
  • used to control diseases caused by phycomycetes, were extremely active in vitro against Pythium ultimum, Phytophthora nicotianae and Phytophthora palmivora. Sporangia production was reduced more than mycelial growth but germination of sporangia and zoospores was relatively unaffected. Less than 1% of the metalaxyl or furalaxyl, present in media at the ED50 for hyphal growth, was firmly absorbed by Phyt. palmivora mycelium; uptake was against a concentration gradient and was characterised by a rapid accumulation followed by a more gradual release. Respiration and wall synthesis were not inhibited, whilst membrane permeability was unaffected. Lipid patterns were altered but these changes were probably of secondary importance. The fungicides inhibited protein and nucleic acid synthesis; RNA production was particularly affected. There was some evidence of a reduction in nuclear division. The primary effect of furalaxyl and metalaxyl probably involves impaired biosynthesis of RNA so that mitosis is inhibited; ofurace may act in the same way.  相似文献   
    7.
    Dose response of weeds to methyl iodide and methyl bromide   总被引:1,自引:0,他引:1  
    Labonuory bioassay and field experiments were conducted to characterize the dose response of weeds to methyl iodide and methyl bromide as soil fumigants. The patterns in potency of both fumigants and in sensitivity of diffcretit weed species to the fumigants were distinguished with the use of logistic dose-response models. Similar to its response to methyl hromide fumigation. Amaranthus retrofleus L. was the most sensitive to methyl iodide fumigation. Cyperus rotundtis L. was the least sensitive to methyl iodide fumigation, whereas Portuloca oleracea L. was the least sensitive to methyl hromide. Lolium multiflorum Lam. Abutilon theophrasti Medik. Chenopodium album L. P. ateracea . Brassica kaber (D.C.) L.C. Wheeler and Cyperus escuden-tus L. were similar in sensitivity to methyl iodide. Methyl iodide was as potent as methyl bromide for A. retroflexus but more potent than methyl bromide for L. multiflorum , A. theophrasti. C. album. P. oleracea. B. kaber, C. esculentus and C. rotundus. The dose response for weeds in the field was similar to that obtained in laboratory bioassays. Under fieid conditions. 280 kg ha-1 methyl iodide killed all species tested except Solanum nigrum L Methyl iodide appears to be a suitable replacement for meihyl bromide because it can be used in situations simitar to methyl bromide fumigation, has superior efficacy against a broad spectrum of pests and has a low potential for degrading the earth's ozone lavers.  相似文献   
    8.
    Landscape metrics with ecotones: pattern under uncertainty   总被引:1,自引:0,他引:1  
      相似文献   
    9.
    The original article to which this Correction refers was published in Pest Management Science 58 (7): 649–662 (2002).Copyright © 2004 Society of Chemical Industry  相似文献   
    10.
    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