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   26265篇
  免费   1715篇
  国内免费   41篇
  28021篇
  2018年   325篇
  2017年   347篇
  2016年   360篇
  2014年   332篇
  2013年   1827篇
  2012年   595篇
  2011年   660篇
  2010年   512篇
  2009年   543篇
  2008年   669篇
  2007年   620篇
  2006年   560篇
  2005年   500篇
  2004年   529篇
  2003年   531篇
  2002年   513篇
  2001年   737篇
  2000年   678篇
  1999年   569篇
  1998年   320篇
  1997年   316篇
  1996年   349篇
  1995年   313篇
  1994年   278篇
  1992年   563篇
  1991年   525篇
  1990年   512篇
  1989年   481篇
  1988年   483篇
  1987年   445篇
  1986年   481篇
  1985年   455篇
  1984年   403篇
  1983年   340篇
  1982年   284篇
  1981年   289篇
  1979年   422篇
  1978年   331篇
  1977年   292篇
  1976年   309篇
  1975年   349篇
  1974年   447篇
  1973年   491篇
  1972年   383篇
  1971年   405篇
  1970年   357篇
  1969年   386篇
  1968年   481篇
  1967年   432篇
  1966年   455篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
281.
The effects on aggressive behavior, open-field activity, and pain threshold of bilateral microinjections of serotonin (20 micrograms) and quipazine (20 micrograms), the direct serotonergic receptor agonist, into the cortico-medial amygdala were investigated in Wistar rats. Both drugs significantly prolonged the attack latency in isolated killer rats (predatory aggression model), and suppressed the incidence of aggressive postures/attacks in shock-induced fighting test (affective aggression). The only difference in the open-field behavior was the lower number of central square entries in drug-treated compared to saline-injected rats. None of the substances produced any significant change in jump threshold. It is concluded that stimulation of serotonin receptors within the amygdala produces inhibition of affective and muricidal behavior in isolated rats. The effect does not seem to be dependent on changes in general activity and pain sensitivity.  相似文献   
282.
Previous studies have examined intra-individual aggregation in the use of cigarettes, alcohol, and coffee by examining the co-occurrent use of any pair of these three substances. A recent literature review failed to find a single investigation that studied use of all three in the same sample. In the present study, co-occurrent use of all three of these substances was examined in crossvalidated subsamples of 226 male and 245 female healthy, community-living, middle-class Americans. A log-linear analysis was used to compare the proportion of smokers, ex-smokers, and nonsmokers categorized as users of more or less amounts of coffee and alcohol. Although most of the intercorrelations were not strong, the results indicate that for both sexes, smokers and ex-smokers were more likely than nonsmokers to drink greater amounts of alcohol and coffee. Furthermore, for smokers, ex-smokers, and nonsmokers, a majority of individuals who reported drinking more alcohol also reported drinking more coffee. Interestingly, the coffee and alcohol consumption levels of ex-smokers resembled those of smokers more than those of nonsmokers. Also, ex-smokers reported drinking more wine and decaffeinated coffee than either smokers or nonsmokers. Finally, the number of cigarettes smoked per day (daily quantity) was positively related to total alcohol and coffee consumption in men, but not in women. Further studies are recommended to examine the role of individual differences in the development, maintenance, and modification of these three appetitive habits and their co-occurrence.  相似文献   
283.
The Jenkins Activity Survey (JAS) and the Framingham Type A Scale (FTAS) have been found to have different psychological correlates. The JAS is typically unrelated to anxiety, while the FTAS is consistently correlated with trait anxiety. The present study of 200 male and female college students clarifies further the psychological heterogeneity of these measures. Enhanced motivation to control the environment has been suggested as an underlying psychological component of Type A behavior (Glass, 1977). Dysphoric emotions and the perception of more environmental stresses, on the other hand, are typical of neuroticism or negative affectivity (Watson & Clark, 1984). Although the results indicate that the JAS and FTAS are highly correlated, the JAS is more closely related to control motivation than is the FTAS. Further, compared to the JAS, the FTAS is more closely correlated with dysphoric emotions and perceived daily stresses. Thus, the results indicate that the JAS is closely correlated with core psychological components of the Type A pattern, while the FTAS has a relatively unique association with general emotional distress. Such differences may account for the fact that these measures are related to different disease end points.  相似文献   
284.
Two adult male chimpanzees reached through a hole in the wall of their home cage and, by tracking the images of their hands and of an otherwise hidden target object in a mirror or closed-circuit television picture, moved their hands in whichever direction was necessary to make contact with the target object. They discriminated between live video images and tapes and performed effectively when the target objects were presented in novel locations and when the video picture was presented at random in different orientations. There was thus no consistent relation between the location of images on the monitor and the location of their real-world counterparts. Comparable performances in monkeys and nonprimates seem unlikely.  相似文献   
285.
Bornstein’s hypothesis that there is a loss of color discrimination in tropical areas was not supported in earlier research in the Cook Islands. Using a more sensitive color vision test (the Farnsworth-Munsell 100-Hue Test), a loss of color discrimination in the red-purple and blue-green regions of the spectrum was found. The lack of sex differences in this color discrimination loss supports a physiological rather than a genetic explanation of the observed decrement.  相似文献   
286.
Due to the death of a severely disabled infant from Bloomington, Indiana, a series of events set in motion by the U.S. Department of Health and Human Services has resulted in cautions to health care providers. The resulting policies and procedures warn hospital personnel against withholding nutritional sustenance or medical treatment from severely disabled infants. This article presents dimensions that might serve as a background for counselors to assist families in considering options related to disabled infants. These dimensions include the meaning of life, cost to benefit ratio, medical options, legal precedent, and a theological perspective. This issue is related to counseling practice through counselor ethics, values, and the need for information that counselors can provide to parents during the decision process.  相似文献   
287.
Memory research has in the last fifteen years been marked by a considerable interest in context effects. This review begins by examining experimental manipulations of verbal and environmental context in verbal memory. This is followed by a more extensive review of episodic studies of face recognition that have examined the effects of varying the background in which a face is portrayed, the room of testing, and the presence of guided instructions. The relevance of these findings to eyewitness memory is also considered. Discrepancies in the literature are pinpointed with theoretical discussion centering around encoding specificity theory (Tulving & Thomson, 1973) and Baddeley and Woodhead’s (1982) distinction between “independent” (extrinsic) and “interactive” (intrinsic) context effects. The review ends with an evaluation of some recent models of memory and face recognition in an attempt to provide a framework within which to interpret the context effects in the literature.  相似文献   
288.
Catastrophe theory is a new mathematical science that permits some insight into the way in which sudden changes or discontinuities of behavior may occur even though the underlying causative forces are essentially continuous. This article aims to present a nonmathematician’s view of catastrophe applications in clinical psychology. Areas covered include anorexia nervosa, binge eating and drinking, affective disorders, schizophrenia, aggressiveness, and prison disturbances. Where appropriate, therapeutic implications and possible physiological correlates are offered. Examples are given of catastrophe theory’s ability to explain previously inexplicable findings. Attention is drawn to its refutability and predictive value, and hence its scientific respectability.  相似文献   
289.
This article reports the results of 629 subjects in three experiments designed to replicate and extend the phenomenon of vicarious verbal conditioning. Experiment I replicated the finding that subjects who responded most to vicarious verbal conditioning were aware of the contingency involved. Experiment II attempted to examine the effects of prior history with the verbal reinforcer on vicarious verbal conditioning by providing seven groups of subjects with varying classic conditioning histories prior to vicarious verbal conditioning. The null results associated with this experiment were hypothesized to be due to the fact that the vicarious verbal conditioning took place in a language laboratory where the subjects could hear but not see the model. Experiment III replicated Experiment II in a live group context as was done in Experiment I. The results showed a) that vicarious verbal conditioning was again found to take place, b) that associating the verbal reinforcer with a tone or tone plus money via forward classic conditioning potentiated the effects of the verbal reinforcer, c) that backward classic conditioning did not potentiate the reinforcer, d) nor did either of two sensitization procedures potentiate the effects of the verbal reinforcer. Both aware and unaware subjects evidenced vicarious verbal conditioning.  相似文献   
290.
This research was designed to compare time judgments obtained under prospective conditions (in which subjects are instructed to attend to time) and retrospective conditions (in which subjects are unaware that they will be required to judge time). In Experiment 1, subjects prospectively or retrospectively judged the duration of intervals spent performing a perceptual-motor task at different levels of difficulty. The results showed that subjects tested under both research paradigms tended to give increasingly shorter and/or more inaccurate time judgments with increases in nontemporal task demands. Experiment 2 was designed to test the effects of attentional deployment on perceived time by comparing prospective and retrospective judgments under control, selective attention, and divided attention conditions. Both types of time judgments became increasingly inaccurate as attention was more broadly deployed. The results of these experiments are consistent with an attentional allocation model, and they suggest that nontemporal task demands disrupt or interfere with timing in both prospective and retrospective situations.  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