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   42392篇
  免费   1541篇
  国内免费   20篇
  43953篇
  2019年   456篇
  2018年   673篇
  2017年   723篇
  2016年   751篇
  2015年   531篇
  2014年   637篇
  2013年   3292篇
  2012年   1176篇
  2011年   1252篇
  2010年   768篇
  2009年   718篇
  2008年   1022篇
  2007年   1056篇
  2006年   930篇
  2005年   875篇
  2004年   831篇
  2003年   788篇
  2002年   866篇
  2001年   1382篇
  2000年   1346篇
  1999年   1024篇
  1998年   451篇
  1997年   398篇
  1996年   406篇
  1992年   845篇
  1991年   801篇
  1990年   814篇
  1989年   774篇
  1988年   764篇
  1987年   734篇
  1986年   752篇
  1985年   768篇
  1984年   608篇
  1983年   542篇
  1982年   427篇
  1981年   406篇
  1979年   703篇
  1978年   507篇
  1977年   452篇
  1976年   415篇
  1975年   595篇
  1974年   701篇
  1973年   691篇
  1972年   588篇
  1971年   542篇
  1970年   508篇
  1969年   548篇
  1968年   672篇
  1967年   607篇
  1966年   582篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
The purpose of this study was to determine the effects of Type A behavior and family history of hypertension on cardiovascular reactivity to mental stress in a group of employed black women. Measures of heart rate and of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were taken at rest, during a mental arithmetic task, and during the Type A Structured Interview (SI). Results indicated that the Type A behavior pattern was associated with SBP and DBP hyperresponsivity during the SI but not during mental arithmetic. Additionally, certain speech components of the Type A pattern, as well as features of the potential-for-hostility component, were also related to cardiovascular responses during the SI. Family history of hypertension did not influence the cardiovascular parameters either alone or in combination with Type A behavior. The results suggest that many of the cardiovascular response characteristics of the Type A pattern that have been observed in predominantly white samples also hold true for blacks. Replication of these findings with other subgroups of blacks, such as young females and middle-aged males, will help document the generality of these findings within the black population.  相似文献   
73.
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   
74.
75.
76.
77.
78.
79.
80.
This study examined the effect of high and low communication apprehension in conjunction with social and personal settings upon verbal behavior. Step wise multiple discriminant analysis of the data indicated a linear combination of language indices (number of syllables, Noun-Verb/Adjective-Adverb ratio, and phrase repetitions) which discriminated between the high apprehensive-personal setting group and the remaining three groups. Results are discussed relative to theoretical projections and the potential for sensitivity toward communication behavior being operative within the communication apprehension framework.  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