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   207905篇
  免费   8953篇
  国内免费   156篇
  2020年   2810篇
  2019年   3478篇
  2018年   4011篇
  2017年   4385篇
  2016年   4953篇
  2015年   3970篇
  2014年   4833篇
  2013年   23546篇
  2012年   5824篇
  2011年   5369篇
  2010年   4477篇
  2009年   5055篇
  2008年   5289篇
  2007年   4976篇
  2006年   5173篇
  2005年   4985篇
  2004年   4497篇
  2003年   4053篇
  2002年   3880篇
  2001年   5013篇
  2000年   4779篇
  1999年   4190篇
  1998年   2985篇
  1997年   2798篇
  1996年   2707篇
  1995年   2518篇
  1994年   2468篇
  1993年   2447篇
  1992年   3473篇
  1991年   3270篇
  1990年   3147篇
  1989年   2962篇
  1988年   2926篇
  1987年   2870篇
  1986年   2925篇
  1985年   3141篇
  1984年   3000篇
  1983年   2697篇
  1982年   2522篇
  1981年   2489篇
  1980年   2320篇
  1979年   2835篇
  1978年   2495篇
  1977年   2371篇
  1976年   2205篇
  1975年   2468篇
  1974年   2622篇
  1973年   2590篇
  1972年   2119篇
  1968年   2012篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
Are different responses differentially associable with their consequences? An overshadowing design was used to try to answer this question for three responses previously studied in golden hamsters. In Experiment I, scrabbling was rapidly suppressed by electric shock punishment, and it overshadowed a tone which occurred between scrabbling and shock. In Experiment II, no evidence of response-shock association was obtained when open rearing was the punished response, and open rearing did not overshadow the tone. Punishment had some effect on face washing, but there was no statistically significant overshadowing with this response. These results are consistent with the idea that differences in punishment suppression among these three responses have an associative basis. They also demonstrate the usefulness of a novel paradigm for studying “preparedness” of response-reinforcer associations.  相似文献   
202.
203.
204.
205.
206.
By roughly 6 years of age, children acquire the stereotype that men are more competent than women in science, technology, engineering, and mathematics (STEM), potentially leading to greater trust in scientific information provided by men. This study tested whether 3- to 8-year-old children differentially endorsed conflicting information about science and toys presented by male and female informants depicted as a ‘man’ and ‘woman’ (Exp1) or ‘scientists’ (Exp2). Children were expected to endorse toy testimony from gender-matched informants; thus, the key question concerned endorsement of science testimony. In Exp1 (N = 149), boys and girls showed a same-gender informant preference for toy testimony; however, girls endorsed the male informant's testimony more for science than for toys – but only when tested by a male experimenter. In Exp2 (N = 264), boys and girls showed a same-gender preference, irrespective of content. Findings suggest that STEM-related gender stereotypes might lead girls to trust scientific information presented by men over women in certain contexts.  相似文献   
207.
An electronic apparatus using infrared beams for monitoring the movements of individual bees under dark conditions is described. The searching behavior of workers in an arena was monitored over 2-h periods. Mean ambulatory velocity for one bee over a distance of 100 mm was 45.6±1.51 mm/sec (n=45). Thigmokinesis and temporal activity patterns are illustrated.  相似文献   
208.
209.
210.
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