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   641篇
  免费   79篇
  2022年   4篇
  2021年   5篇
  2020年   4篇
  2019年   5篇
  2018年   5篇
  2017年   8篇
  2016年   10篇
  2015年   23篇
  2014年   25篇
  2013年   21篇
  2012年   35篇
  2011年   24篇
  2010年   26篇
  2009年   19篇
  2008年   27篇
  2007年   19篇
  2006年   31篇
  2005年   21篇
  2004年   36篇
  2003年   17篇
  2002年   20篇
  2001年   26篇
  2000年   24篇
  1999年   16篇
  1998年   24篇
  1997年   14篇
  1996年   9篇
  1995年   12篇
  1994年   5篇
  1993年   10篇
  1992年   11篇
  1991年   8篇
  1990年   9篇
  1989年   7篇
  1988年   10篇
  1987年   14篇
  1986年   5篇
  1985年   6篇
  1984年   8篇
  1983年   6篇
  1982年   7篇
  1979年   9篇
  1976年   6篇
  1972年   4篇
  1971年   4篇
  1970年   3篇
  1968年   6篇
  1967年   4篇
  1966年   4篇
  1939年   3篇
排序方式: 共有720条查询结果,搜索用时 15 毫秒
21.
Summary Although Giemsa C-banding techniques have been used extensively for assaying cereal heterochromatin, a more specific technique for analyzing cereal heterochromatin has been developed recently with the isolation of DNA sequences present in heterochromatin and their employment in in situ hybridization to cereal chromosomes. A number of triticales were examined for the occurrence of modified rye chromosomes using the in situ hybridization technique. With a heterogeneous sequence probe the amount of rye heterochromatin appears to be relatively constant in wheat backgrounds but when a specific sequence probe was employed variation was observed. Whether this variation reflects polymorphism in rye or whether it is a result of adaption of the rye genome to coexistence with the wheat genome in triticales is discussed. — The triticale Rosner was examined in detail and it was established that the rye chromosome 2R had been replaced by the wheat chromosome 2D.  相似文献   
22.
The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.  相似文献   
23.
24.
25.
26.
27.
28.

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.  相似文献   
29.
30.
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