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   82976篇
  免费   2919篇
  国内免费   46篇
林业   3180篇
农学   2477篇
基础科学   462篇
  9847篇
综合类   13207篇
农作物   2879篇
水产渔业   3961篇
畜牧兽医   43906篇
园艺   937篇
植物保护   5085篇
  2018年   1249篇
  2017年   1330篇
  2016年   1223篇
  2015年   1046篇
  2014年   1228篇
  2013年   3361篇
  2012年   2302篇
  2011年   2801篇
  2010年   1849篇
  2009年   1811篇
  2008年   2696篇
  2007年   2622篇
  2006年   2399篇
  2005年   2174篇
  2004年   2053篇
  2003年   2140篇
  2002年   1982篇
  2001年   2478篇
  2000年   2440篇
  1999年   1993篇
  1998年   851篇
  1997年   850篇
  1995年   866篇
  1994年   792篇
  1993年   772篇
  1992年   1569篇
  1991年   1813篇
  1990年   1625篇
  1989年   1607篇
  1988年   1475篇
  1987年   1472篇
  1986年   1482篇
  1985年   1500篇
  1984年   1241篇
  1983年   1133篇
  1982年   784篇
  1979年   1230篇
  1978年   951篇
  1977年   943篇
  1976年   962篇
  1975年   992篇
  1974年   1141篇
  1973年   1115篇
  1972年   1059篇
  1971年   945篇
  1970年   960篇
  1969年   977篇
  1968年   887篇
  1967年   939篇
  1966年   814篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Applications of 1, 2, 4, 6 and 12 lit. of spray per tree, each volume containing 6 g. of dimethoate a.i., did not show significant differences between the treatments, but olive fly pupae and third instar larvae were found to be more resistant than first and second instar larvae. Also, no differences became apparent between treatments with Dimecron 50, Carbicron 50 and Nuvacron 50 at rates of 7, 10 and 14 c.c. per tree respectively; these experiments will be continued.  相似文献   
32.
33.
B. Maris 《Euphytica》1961,10(3):269-276
The occurrence and the nomenclature of the new physiologic races of the wart causing fungus Synchytrium endobioticum are treated. A list of varieties resistant to at least one new race has been included and also a list of differentials for the identification of the various races of the fungus. Finally details are given of testing Dutch potato varieties for resistance against race 6 while some results are mentioned of investigations concerning the inheritance of the resistance against this race.  相似文献   
34.
35.
36.
37.
Berichtigung     
Ohne Zusammenfassung  相似文献   
38.
Pollination of strawberries by honey-bees increased the percentage of flowers that set fruit, the weight of the berries, and the percentage of well-formed berries.  相似文献   
39.
Plant growth regulators were applied to the foliage and immature fruit clusters of the stenospermic grape selection ‘C35-33’ at various periods before bloom to stimulate viable seed development. In the 1987 season five different plant growth regulators were used, but in 1988 the growth retardants Cycocel and XE-1019 were used exclusively. Chemical treatments applied 35 days after bud break increased significantly germination percentage. Experimental results indicate that the use of certain plant growth regulators may aid in increasing the efficiency of seedless grape breeding by providing an alternative to in-ovulo embryo culture.  相似文献   
40.
The proteins of wheat flour have several biological activities that can affect human health and physiology when wheat-based foods are consumed. The modifications of bread crumb and crust proteins during an in vitro peptic/pancreatic digestion process were studied by electrophoresis and immunoblotting with polyclonal antibodies specific for single proteins or groups of homologous proteins of the wheat flour, and the results were compared to those obtained for an unheated dough sample. The results show that baking affects the extent of proteolysis and the immunological and physicochemical features of the digestion products in relation to the level of the heat treatment. Therefore, the results concerning the digestion of the unheated wheat flour or dough are not representative of what happens when baked products enter the human digestive tract.  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