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   57701篇
  免费   1550篇
  国内免费   15篇
  2020年   451篇
  2019年   560篇
  2018年   4025篇
  2017年   3447篇
  2016年   2952篇
  2015年   766篇
  2014年   794篇
  2013年   3093篇
  2012年   1820篇
  2011年   3561篇
  2010年   3195篇
  2009年   2192篇
  2008年   2773篇
  2007年   3229篇
  2006年   1065篇
  2005年   1127篇
  2004年   1029篇
  2003年   909篇
  2002年   902篇
  2001年   1203篇
  2000年   1182篇
  1999年   894篇
  1998年   408篇
  1997年   402篇
  1996年   358篇
  1995年   361篇
  1992年   749篇
  1991年   656篇
  1990年   713篇
  1989年   613篇
  1988年   650篇
  1987年   604篇
  1986年   607篇
  1985年   560篇
  1984年   523篇
  1983年   491篇
  1980年   356篇
  1979年   585篇
  1978年   411篇
  1977年   360篇
  1975年   467篇
  1974年   498篇
  1973年   542篇
  1972年   401篇
  1971年   400篇
  1970年   358篇
  1969年   406篇
  1968年   483篇
  1967年   443篇
  1966年   359篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
871.
Three experiments were conducted to investigate the theoretical reduction of rate and duration of reinforcement to their product, rate of reinforcement-time, under concurrent chain schedules. In Exp. I, rate of reinforcement-time was varied by varying rate of reinforcement delivery, holding duration of reinforcement availability constant; in Exp. II, rate of reinforcement-time was varied by holding rate of reinforcement delivery constant and varying duration of reinforcement availability; in Exp. III, rate of reinforcement-time was held constant by varying both rate and duration of reinforcement simultaneously and inversely. For all three experiments, both relative rate of responding and relative time spent in the initial link were found to match approximately the relative rate of reinforcement-time arranged in the terminal link. These data were interpreted as support for the notion that rate and duration of reinforcement may be functionally equivalent and reducible to a single variable, rate of reinforcement-time.  相似文献   
872.
Some punishing effects of response-force   总被引:1,自引:1,他引:0       下载免费PDF全文
The present experiment explored the punishing effect of different response-force requirements by means of a two-operant design analogous to a two-component chain schedule. The first component of the chain required a lever pull through 0.25 in. (0.64 cm) at 1 lb (4.45 N) of force. The second component required a lever pull through an additional 0.75 in. (1.90 cm) with the force varied between sessions from 1 lb to 50 lb (4.45 N to 223 N). Completion of the second component of the chain was reinforced after variable intervals averaging 1 min. The average rate of first-component response decreased as the force requirement for second-component responses was increased. This rate reduction did not appear to be due to increased response duration, “fatigue”, or differing rates of reinforcement. If the force requirement for the second-component response is viewed as a consequence for the first-component response, then the results of the experiment show that a high force requirement is a punisher.  相似文献   
873.
874.
875.
876.
This study was undertaken to examine ambiguities in the ability of the I-E scale to predict complex social behavior. An analysis of the items in the I-E scale suggested that the scale might contain a conservative bias Further, it was suggested that responses to the items may be determined by the individual's political and social ideology, which in turn are influenced by the political and social norms to which he has been exposed The sample consisted of one parent and a college-aged child from 60 upper-middle-class families in which the parent was visible in the community for political and social participation, half the parents interviewed were liberal, and half conservative in their political views A number of measures of political and social participation were administered, along with a shortened version of the I-E scale The findings of the study supported the contention that the “internal” items on the I-E scale are more congenial to persons holding conservative political views than for those holding liberal views. Perceived internal causality, as measured by the I-E scale, was found to be nonsignificantly correlated with any of the measures of political participation for the parent sample, with five of the six correlations being in the opposite direction from that predicted by social learning theory The results of the study were discussed in terms of White's distinction between the “moralizer” and “reformer” approach to social problems The validity of the I-E scale as a measure of a stable personality trait was called into question, as was its usefulness in predicting complex social behavior  相似文献   
877.
Three groups of pigeons were trained on a red-green discrimination in which the stimuli were alternately presented in a multiple schedule of reinforcement. The discrimination was reversed 24 times. Groups were given 1, 2, or 4 hr of training on each discrimination. Increasing the length of training had two principal effects on reversal performance: it increased the rate of extinction of responding to one of the stimuli and increased the rate of reacquisition of responding to the other. The latter effect involved both an increase in reacquisition of responding to a positive stimulus within reversals and an increase in recovery of responding to the previous negative stimulus between reversals. Improvements in performance of each group over the series of reversals were qualitatively similar to the two effects of length of training on each discrimination, and were analogous to effects obtained in other studies involving overtraining and successive reversals of simultaneous discriminations.  相似文献   
878.
879.
880.
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