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   30277篇
  免费   1372篇
  国内免费   27篇
  31676篇
  2021年   249篇
  2020年   429篇
  2019年   499篇
  2018年   704篇
  2017年   704篇
  2016年   736篇
  2015年   539篇
  2014年   639篇
  2013年   2821篇
  2012年   1156篇
  2011年   1261篇
  2010年   748篇
  2009年   756篇
  2008年   1019篇
  2007年   992篇
  2006年   953篇
  2005年   841篇
  2004年   801篇
  2003年   811篇
  2002年   805篇
  2001年   946篇
  2000年   918篇
  1999年   677篇
  1998年   376篇
  1997年   378篇
  1996年   322篇
  1995年   303篇
  1994年   271篇
  1993年   294篇
  1992年   495篇
  1991年   474篇
  1990年   479篇
  1989年   448篇
  1988年   402篇
  1987年   400篇
  1986年   441篇
  1985年   451篇
  1984年   396篇
  1983年   331篇
  1982年   253篇
  1981年   274篇
  1979年   296篇
  1978年   278篇
  1977年   238篇
  1976年   230篇
  1975年   281篇
  1974年   344篇
  1973年   281篇
  1972年   260篇
  1969年   238篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
122.
In two experiments, key pecking of pigeons was maintained by a variable-interval 180-s schedule of food presentation. Conjointly, a second schedule delivered response-dependent electric shock. In the first experiment, shocks were presented according to either a variable-interval or a nondifferential interval-percentile schedule. The variable-interval shock schedule differentially delivered shocks following long interresponse times. Although the nondifferential shock schedules delivered shocks less differentially with respect to interresponse times, the two shock schedules equally reduced the relative frequency of long interresponse times. The second experiment differentially shocked long or short interresponse times in different conditions, with resulting decreases in the relative frequency of the targeted interresponse times. These experiments highlight the importance of selecting the appropriate level of analysis for the interaction of behavior and environment. Orderly relations present at one level of analysis (e.g., interresponse times) may not be revealed at other levels of analysis (e.g., overall response rate).  相似文献   
123.
Our discussion begins with a consideration of the various types of religion and of guilt. Both religion and morality function in different ways from individual to individual. All these factors need to be taken into account before we can turn to treatment for the painful experience of guilt and bring about an improved self-esteem.  相似文献   
124.
ALCOVE: an exemplar-based connectionist model of category learning.   总被引:16,自引:0,他引:16  
ALCOVE (attention learning covering map) is a connectionist model of category learning that incorporates an exemplar-based representation (Medin & Schaffer, 1978; Nosofsky, 1986) with error-driven learning (Gluck & Bower, 1988; Rumelhart, Hinton, & Williams, 1986). Alcove selectively attends to relevant stimulus dimensions, is sensitive to correlated dimensions, can account for a form of base-rate neglect, does not suffer catastrophic forgetting, and can exhibit 3-stage (U-shaped) learning of high-frequency exceptions to rules, whereas such effects are not easily accounted for by models using other combinations of representation and learning method.  相似文献   
125.
Less is known about the effects of primary relationships on psychological health for homosexual men and women than for heterosexual men and women. Given the HIV/AIDS epidemic, the primary relationships of homosexual men are especially important to examine at the present time. Using questionnaire data collected from 259 homosexual men, this study examined the effects of status and quality of relationship on psychological health. Analysis indicated that homosexual men who are in primary relationships experience fewer depressive symptoms and greater well-being than other homosexual men but that being in a relationship does not predict changes in these outcomes over time. Men who report high quality of relationship show improvements over time in psychological health. These findings are discussed in light of the HIV/AIDS epidemic.  相似文献   
126.
This article examined the relationship between impulsiveness and attitudes toward institutional authority among Australian secondary school students. Reliable questionnaire measures of these constructs were completed by 48 boys and 57 girls, about 14 years of age. Correlations between impulsiveness and attitude to authority differed between the sexes, with a significant negative correlation of -.43 being obtained for boys only.  相似文献   
127.
Analyses of responses from a clinical sample of 120 patients (primarily schizophrenics) and from 158 college students to the Cognitive Slippage Scale, a scale designed by Miers and Raulin to identify speech deficits and confused thinking in schizophrenic and schizotypal personality disorders showed high internal reliability; Cronbach's coefficients alpha were .89 and .86 in the clinical and college student samples, respectively. The mean scale scores significantly differentiated the two samples. Also, change scores over 4 wk. showed adequate stability for both samples. Item analysis indicated Items 11, 20, 21, and 28 may not reliably discriminate between schizophrenic and college student samples. Over-all, these preliminary results are consistent with the reliability and validity of the scale.  相似文献   
128.
At the present, it is unknown how restraint and binge eating/counterregulation are exactly related. Earlier studies on this relationship suffer from two main shortcomings: the studies are all correlational in nature or could not rule out the contribution of confounding variables such as weight loss. The present study investigated whether a break of restraint is a sufficient condition for the occurrence of counterregulation by studying a restrained sample which is not liable to dieting practices and weight loss. The externally imposed restraint on children with regard to eating sweets was broken. However, after breaking their external restraint the children did not counterregulate. It is discussed whether restraint of food intake is really as important for binge eating as it is claimed to be or whether it is merely a consequence or an epiphenomenon of binge eating.  相似文献   
129.
Psychological research is increasingly involved in debates regarding abortion. While recognizing the diversity of ethical and moral issues intertwined with abortion, the American Psychological Association (APA) has focused its involvement on psychological factors, most recently by appointing an expert panel to review the literature on psychological effects. This article notes the history of APA involvement and reports on the panel's conclusions. It presents evidence that abortion is not likely to be followed by severe psychological responses and that psychological aspects can best be understood within a framework of normal stress and coping rather than a model of psychopathology. Correlates of more negative responses following abortion are also discussed.  相似文献   
130.
A biodevelopmental model of insomnia is articulated specifying coordinated nighttime (disturbed sleep pattern) and daytime (no excessive daytime sleepiness) characteristics defining an insomnoid classification in at-risk groups: short sleepers and older adults. Pupillometry is proposed as a useful means of discriminating degree of daytime sleepiness to aid in the differential diagnosis of insomnia and insomnoid states, and the present study tested the discriminative validity of this approach. Noninsomniac (n = 34) and insomniac (n = 29) college students submitted to four 10 min pupillometry sessions tracking daytime sleepiness from morning arising to bedtime. Pupil diameter proved to be an able discriminator of these two groups though substantial overlap of the two distributions was also noted. The results supported the sensitivity of pupillometry in detecting daytime sleepiness, but yielded alternative interpretations. We observed statistical differentiation in insomniac and noninsomniac daytime sleepiness, but substantial, functional overlap between these groups. Assessment and treatment implications arising from the biodevelopmental model were hypothesized.  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