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   22335篇
  免费   751篇
  国内免费   11篇
  23097篇
  2020年   204篇
  2019年   211篇
  2018年   317篇
  2017年   364篇
  2016年   361篇
  2015年   229篇
  2014年   303篇
  2013年   1638篇
  2012年   601篇
  2011年   653篇
  2010年   402篇
  2009年   378篇
  2008年   554篇
  2007年   545篇
  2006年   498篇
  2005年   450篇
  2004年   437篇
  2003年   401篇
  2002年   453篇
  2001年   721篇
  2000年   742篇
  1999年   552篇
  1998年   254篇
  1997年   215篇
  1992年   448篇
  1991年   406篇
  1990年   441篇
  1989年   414篇
  1988年   396篇
  1987年   398篇
  1986年   404篇
  1985年   421篇
  1984年   334篇
  1983年   299篇
  1982年   237篇
  1981年   212篇
  1979年   386篇
  1978年   278篇
  1977年   253篇
  1976年   224篇
  1975年   344篇
  1974年   372篇
  1973年   351篇
  1972年   329篇
  1971年   287篇
  1970年   260篇
  1969年   321篇
  1968年   358篇
  1967年   321篇
  1966年   325篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
A square-wave grating from which the fundamental harmonic has been subtracted (missing fundamental grating) when viewed from a suitable distance appears similar to another grating of periodicity three times higher. The neurons of the visual cortex of the cat, in a given range of spatial frequencies characteristic of each cell, give similar responses to the two gratings.  相似文献   
32.
33.
Gábor L. Ambrus 《Zygon》2020,55(4):875-897
We are easily misguided as to the true nature of Facebook, and tend to treat it simply as a powerful technological instrument in the service of human intentions. We can, however, gain a better picture of it through recourse to the Jewish tradition of the golem, an image of human beings, created by them in a re-enactment of their own creation by God. It turns into a magic servant in modernity with an inherent dynamic running between its human and its subhuman characteristics. This dynamic is the main cause behind its becoming uncontrollable. In like manner, what is subhuman in Facebook serves its masters and functions under their total control, but also empowers Facebook's increasingly human operation, an algorithm-based capability which raises growing doubts about what counts as human. Facebook implies the crisis of humanity which coincides with the “death of God,” that is, the obsolescence of the idea of a divine creator.  相似文献   
34.
Previous research has revealed that individuals have expectations for the development of romance based on personal experience and cultural images. A series of research questions and hypotheses was generated and a sequence of hierarchical log-linear analysis models axis developed to test (a) the effect of gender and knowledge of relational stage and relationship type on prediction of next-occurring actions in the development of a romance, (b) the use of compliance-gaining strategies intended to advance a relationship to the next stage, and (c) justification of secondary goals in which participants reported why they chose the strategies they did as opposed to other alternatives. The data revealed effects for relational stage progression on prediction of ensuing actions. Ingratiation, explanation, and direct requests were popular strategies for developing intimacy. Gender differences in terms of secondary goals were reported. Results are discussed in terms of relational memory structures for the development of intimacy.  相似文献   
35.
36.
Three experiments used a discriminated operant procedure to study conditional discrimination learning in rats. The first experiment showed that rats were capable of learning a biconditional discrimination in which two contexts served as conditional cues signalling the reinforcement contingencies associated with two discriminative stimuli. The discrimination was learned equally well when one discriminative stimulus signalled food, the other its absence, and when one stimulus signalled food, the other extinction plus mild footshock.

In Experiment 2 it was shown that prior training on such a conditional discrimination enhanced the subsequent context specificity of simple conditioning relative to control groups of animals for whom the prior training had not been conditional. Experiment 3 showed that a reversal of the significance of one pair of discriminative stimuli produced no spontaneous reversal in performance to a second, target, pair.

The pattern of results is best accounted for by an analysis of contextual conditional discrimination learning in terms of stimulus configurations and offers no support for the notion that rats may learn a general conditional rule or set.  相似文献   
37.
38.
39.
40.
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