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   300篇
  免费   33篇
  2023年   2篇
  2021年   7篇
  2020年   8篇
  2019年   1篇
  2018年   6篇
  2017年   8篇
  2016年   18篇
  2015年   37篇
  2014年   27篇
  2013年   34篇
  2012年   9篇
  2011年   6篇
  2010年   18篇
  2009年   25篇
  2008年   7篇
  2007年   8篇
  2006年   8篇
  2005年   6篇
  2004年   4篇
  2003年   5篇
  2002年   7篇
  2001年   1篇
  2000年   5篇
  1999年   8篇
  1998年   4篇
  1997年   2篇
  1996年   5篇
  1995年   1篇
  1994年   2篇
  1993年   5篇
  1992年   4篇
  1991年   5篇
  1990年   2篇
  1988年   2篇
  1987年   3篇
  1986年   5篇
  1985年   5篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1979年   1篇
  1977年   1篇
  1974年   1篇
  1972年   5篇
  1971年   4篇
  1969年   2篇
  1968年   1篇
  1967年   2篇
  1958年   1篇
排序方式: 共有333条查询结果,搜索用时 15 毫秒
1.
2.
Using ethnographic data collected in a second grade classroom over the course of a school year, this paper describes the ways in which one school's discourse of liberalism is deleteriously deployed. We view the school's discipline creed as emblematic of the school's liberal curriculum, and interrogate the effects on four African American boys in the classroom when the school enacts this creed. Despite the agency that these boys obviously had, they were unable to control the ways in which they were placed at a structural disadvantage and manipulated by a system far more powerful than they were. The results were that these four boys suffered. Not only did the intended liberal curriculum fail to be translated fully into the enacted curriculum, the liberal underpinnings of this curriculum precluded teachers and students from taking any critical stance.  相似文献   
3.
Excised cotyledons of Pinus radiata D. Don cultured under shoot-forming(plus benzyladenine) and non shoot-forming (minus benzyladenine)conditions for 10 and 21 days were fed U-[14C]-glucose for 3h in the light followed by a 3 h chase period. The labellingof individual metabolites as well as 14C incorporation intoprotein was assessed. It was found that the general metabolicpatterns were qualitatively the same in shoot-forming and nonshoot-forming conditions, however, metabolism leading to respirationas well as to the synthesis of some amino acids and proteinsynthesis was enhanced in the shoot-forming cultures. (Received February 16, 1987; Accepted July 8, 1987)  相似文献   
4.
The effect of ascorbic acid on growth and shoot formation in callus cultures of tobacco (Nicotiana tabacum L.) was investigated, using young (4–12 subcultures) and old (more than 30 subcultures) tissue. It was found that ascorbate, at levels of 4–8×10-4M, enhanced shoot formation in both young and old callus. Treatment with ascorbate also speeded up the shoot-forming process. In addition, ascorbate completely reversed the inhibition of shoot formation by gibberellic acid in young callus, but was less effective in old callus.  相似文献   
5.
6.
Histocompatibility Gene Organization and Mixed Lymphocyte Reaction   总被引:3,自引:0,他引:3  
TRANSFORMATION of allogenic lymphocytes in mixed cultures depends chiefly on an incompatibility between the lymphocyte donors at the major histocompatibility locus in man (HL-A), mouse (H-2) and rat (H-l)1. Although the mouse H-2 locus can be divided into several regions each of which controls one or more antigenic specificities2 and two or more subloci control HL-A antigens in man3, it is not known whether all parts of the major histocompatibility locus are equally important in eliciting transformation in mixed lymphocyte cultures. We now show that capacity to elicit lymphocyte transformation is different for different parts of the mouse H-2 locus.  相似文献   
7.
8.
9.
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