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   10314篇
  免费   35篇
  10349篇
  2019年   24篇
  2018年   1527篇
  2017年   1368篇
  2016年   995篇
  2015年   50篇
  2014年   24篇
  2013年   145篇
  2012年   297篇
  2011年   1144篇
  2010年   1151篇
  2009年   643篇
  2008年   828篇
  2007年   1123篇
  2006年   38篇
  2005年   118篇
  2004年   85篇
  2003年   68篇
  2002年   54篇
  2001年   66篇
  2000年   69篇
  1999年   48篇
  1998年   24篇
  1997年   15篇
  1996年   9篇
  1995年   11篇
  1993年   12篇
  1992年   12篇
  1991年   24篇
  1990年   31篇
  1989年   17篇
  1988年   13篇
  1987年   16篇
  1986年   18篇
  1985年   18篇
  1984年   8篇
  1983年   11篇
  1982年   12篇
  1980年   8篇
  1979年   9篇
  1978年   14篇
  1976年   13篇
  1975年   13篇
  1974年   7篇
  1973年   15篇
  1972年   11篇
  1970年   13篇
  1969年   11篇
  1968年   14篇
  1967年   10篇
  1966年   7篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
74.
75.
76.
77.
78.
Journal of Philosophical Logic - This paper is concerned with counterfactual logic and its implications for the modal status of mathematical claims. It is most directly a response to an ambitious...  相似文献   
79.
Selective breeding of wild rats over many generations on the basis of low or high defensive threat and attack to human approach and contact has produced highly polarized “domesticated” and “wild-type” animals. Because the selection procedure selectively involves these two defense patterns, and these clearly differ in the two groups, it is of interest to determine if other, nonselected, defensive behaviors to threat stimuli also change. “Domesticated” and “wild-type” rats of the thirty-fifth generation were run in a fear defense test battery (F/DTB) to systematically evaluate defensive behaviors to a variety of present threat stimuli. “Domesticated” rats showed reduced avoidance and slower flight speed to an approaching experimenter, reduced jump/startle response to handelap and dorsal contact, less vocalization and boxing to vibrissae stimulation or to an anesthetized conspecific, and reduced defensiveness to an attempted pickup by the experimenter. These results indicate that selective bi-directional breeding for defensive threat and attack to human approach and contact produces group differences in a variety of defensive behaviors, and in defensiveness to stimuli other than those on which the selection was based. © 1994 Wiley-Liss, Inc.  相似文献   
80.
The experiments were performed on adult male cats selected initially as good mousekillers. Cats were tested in pairs and each pair was introduced separately to the experimental compartment. The attitude toward the partner before and during the predatory competition test as well as superiority in catching and killing the mice, considered as an index of dominance, were registered. In the course of experiment five types of relations between the predatory dominance and aggressive behavior were observed. The concept of dominance as an outcome of several factors was discussed. It was concluded that predatory dominance is not based exclusively on aggressive mechanisms, as it may be formed and sustained without overt aggression.  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