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   23643篇
  免费   818篇
  国内免费   12篇
  24473篇
  2020年   234篇
  2019年   253篇
  2018年   382篇
  2017年   415篇
  2016年   420篇
  2015年   270篇
  2014年   370篇
  2013年   1791篇
  2012年   699篇
  2011年   756篇
  2010年   455篇
  2009年   437篇
  2008年   622篇
  2007年   609篇
  2006年   545篇
  2005年   498篇
  2004年   480篇
  2003年   445篇
  2002年   489篇
  2001年   738篇
  2000年   753篇
  1999年   563篇
  1998年   268篇
  1997年   223篇
  1992年   453篇
  1991年   410篇
  1990年   445篇
  1989年   417篇
  1988年   398篇
  1987年   402篇
  1986年   406篇
  1985年   423篇
  1984年   335篇
  1983年   302篇
  1982年   242篇
  1981年   214篇
  1979年   388篇
  1978年   282篇
  1977年   254篇
  1976年   223篇
  1975年   344篇
  1974年   373篇
  1973年   354篇
  1972年   328篇
  1971年   289篇
  1970年   261篇
  1969年   325篇
  1968年   360篇
  1967年   324篇
  1966年   327篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
901.
In the first experiment rats were given either 16 or 48 nonrewarded or continuously rewarded trials prior to 24 continuously or partially rewarded trials, followed by extinction. Increased resistance to extinction was found for increasing numbers of nonrewarded trials when they were followed by partial reward, but not when followed by continuous reward. Similarly, more continuously rewarded trials followed by partial reward tended to increase resistance to extinction. Because of the theoretical importance of the effect of continuous reward followed by partial, a second experiment was performed where the range of the number of continuously rewarded trials was extended to 0, 48, and 96. Contrary to many theoretical predictions, resistance to extinction increased as a function of increasing amounts of continuous reward.  相似文献   
902.
The effects of subliminal stimulation on masculinity-femininity ratings of a male model were tested for 100 male undergraduates, randomly divided into four groups and individually shown a slide of a male model. One group received no further stimulation. A second group received a subliminal flash of white light across the image of the model; a third group was presented with the subliminal message "masculine," while a fourth group was presented with the subliminal message "feminine." Subjects were asked to rate the model on a six-point scale of masculinity-femininity. The differences in ratings among groups were not significant, indicating that subliminal stimulation did not influence masculinity-femininity value-norm-anchor judgments. There were no significant differences in the reported perception of additional stimuli or the tendency to be relaxed among the four groups. However, subjects who received the "masculine" message and reported that they were more relaxed did tend to rate the model higher in masculinity.  相似文献   
903.
Preference for stimulus complexity across the life-span was investigated with 175 females ranging in age from 17 to 72 yr. of age. Preference for complexity appeared to be age-invariant and monotonic function. Relationships to previous findings are discussed.  相似文献   
904.
The antidepressants desipramine and imipramine were compared within the framework of a multiclinical study performed under the conditions of a controlled clinical experiment. There has been found a time-different remission of affective symptoms, which was not detectable for the inhibition of drive. The tachythymoleptic action of desipramine is discussed with reference to these results. Evaluation of the possibility of controlling affects shows different ranges of activity of desipramine and imipramine, with desipramine influencing especially negative psychoenergetic symptoms in the area of drives and emotions and imipramine, restrictive symptoms in addition to differential phenomena of the psychomotor expression.  相似文献   
905.
The author gives a brief survey of the development of Child-Neuropsychiatry in the G.D.R. and subsequently gives reasons for the decision in favor of the unity of neurology and psychiatry as applied to children and juveniles, which is in contrast to developments in other countries. In addition to hygienic, economic, organizational, and medical considerations, this decision was also determined by the fact that a Child-Neuropsychiatrist must, in his practical work as a subspecialist, be able to head a multiprofessional team and, thus, help assure optimum development of a child's personality.  相似文献   
906.
U-statistic hierarchical clustering   总被引:2,自引:0,他引:2  
A monotone invariant method of hierarchical clustering based on the Mann-Whitney U-statistic is presented. The effectiveness of the complete-link, single-link, and U-statistic methods in recovering tree structures from error perturbed data are evaluated. The U-statistic method is found to be consistently more effective in recovering the original tree structures than either the single-link or complete-link methods.  相似文献   
907.
908.
909.
910.
The validity of Ramsey's three factor model of vocational commitment – consisting of ego-involvement (ranging from altruism to self-orientation), pre-dispositions, and occupational possibilities – is examined Although no data is provided relevant to the altruism end of the ego-involvement continuum, analyses of data from a sample of trainee nurses indicated that the three measures of self-orientation, predispositions, and occupational possibilities possessed satisfactory internal consistency and discriminant validity, thus providing support for the three-dimensional model.  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