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   51317篇
  免费   1210篇
  国内免费   14篇
  2020年   347篇
  2019年   374篇
  2018年   3912篇
  2017年   3220篇
  2016年   2761篇
  2015年   579篇
  2014年   612篇
  2013年   2685篇
  2012年   1467篇
  2011年   3293篇
  2010年   3012篇
  2009年   2088篇
  2008年   2541篇
  2007年   3020篇
  2006年   939篇
  2005年   1006篇
  2004年   919篇
  2003年   871篇
  2002年   786篇
  2001年   971篇
  2000年   1003篇
  1999年   746篇
  1998年   420篇
  1997年   381篇
  1996年   357篇
  1995年   334篇
  1994年   316篇
  1992年   616篇
  1991年   546篇
  1990年   605篇
  1989年   521篇
  1988年   494篇
  1987年   487篇
  1986年   506篇
  1985年   573篇
  1984年   478篇
  1983年   430篇
  1982年   382篇
  1981年   347篇
  1980年   333篇
  1979年   436篇
  1978年   413篇
  1977年   350篇
  1976年   337篇
  1975年   433篇
  1974年   482篇
  1973年   481篇
  1972年   377篇
  1968年   359篇
  1966年   324篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
The old homeless and the new homelessness in historical perspective   总被引:2,自引:0,他引:2  
In the 1950s and 1960s homelessness declined to the point that researchers were predicting its virtual disappearance in the 1970s. Instead, in the 1980s, homelessness increased rapidly and drastically changed in composition. The "old homeless" of the 1950s were mainly old men living in cheap hotels on skid rows. The new homeless were much younger, more likely to be minority group members, suffering from greater poverty, and with access to poorer sleeping quarters. In addition, homeless women and families appeared in significant numbers. However, there were also points of similarity, especially high levels of mental illness and substance abuse.  相似文献   
982.
983.
Wordshape errors in language production   总被引:1,自引:0,他引:1  
J P Stemberger 《Cognition》1990,35(2):123-157
Errors in natural speech that crucially involve the shape of the target word, i.e. interact in some way with the number of consonants and vowels in the word and their relative positioning, are examined in detail. It is shown that context highly constrains the rate of such errors. The data implicate a distinction between a segment level that encodes fine phonemic distinctions and a wordshape level with a course encoding. Implications for the representation of language and cognitive processing in language production are explored.  相似文献   
984.
Meta-logical problems: knights, knaves, and Rips   总被引:1,自引:0,他引:1  
P N Johnson-Laird  R M Byrne 《Cognition》1990,36(1):69-84; discussion 85-90
  相似文献   
985.
Escape and avoidance that are disproportional to the danger of the pertinent stimulus are important clinical problems that are often related to inaccurate (catastrophic) expectations. One possible source of such expectations is a prior, underestimated aversive experience. In the present experiment the hypotheses that underestimated pain leads to escape and that it leads to avoidance were tested. In order to control for the effect of the intensity of the pain stimulus, a control group that received 20 pain stimuli of high intensity was formed. Subjects in the experimental condition received 17 pain stimuli of low intensity and 3 of (unexpectedly) high intensity (experimentally induced underprediction). Underprediction of the high intensity stimulus was significantly related to escape, but not to avoidance. The results suggest that the way in which avoidance was operationalized accounts for this. The strong support of the hypothesized relationship between underpredicted pain and escape is an important finding, however.  相似文献   
986.
A rationale for, and data from, a trial of a theory of item generation by algorithms whose origins are cognitive models of task performance are presented. Since Spearman (1904), intelligence has been operationally defined and assessed in human subjects by administering identical test items whose content and order have been fixed only after empirical iterations. In our approach, intelligence is ostensively defined by theoretically determined algorithms used for item construction and presentation. Knowledge of what cognitive factors limit human performance makes it possible to vary within tightly specified parameters those features of the tasks that contribute to difficulty, which we call radicals, to let those components of the tasks that do not contribute to difficulty vary randomly, and to counterbalance aspects of answer production that might induce biases of response. Empirical data are based on the generation of five different short tests demanding only functional literacy as a prerequisite for their execution. Four parallel forms of each test were administered to young male Army recruits whose scores were collated with their Army Entrance Test results, which were not previously known to us. Results show that the parallel, algorithm-generated item sets are statistically invariant, which item generation theory demands; and that the individual tests differentially predict Army Entrance Test scores. We conclude that IQ test performances are parsimoniously explained by individual differences in encoding, comparison and reconstructive memory processes.  相似文献   
987.
988.
Numerical abstraction by human infants   总被引:9,自引:0,他引:9  
P Starkey  E S Spelke  R Gelman 《Cognition》1990,36(2):97-127
Across several experiments, 6- to 8-month-old human infants were found to detect numerical correspondences between sets of entities presented in different sensory modalities and bearing no natural relation to one another. At the basis of this ability, we argue, is a sensitivity to numerosity, an abstract property of collections of objects and events. Our findings provide evidence that the emergence of the earliest numerical abilities does not depend upon the development of language or complex actions, or upon cultural experience with number.  相似文献   
989.
Event representation in Pavlovian conditioning: image and action   总被引:1,自引:0,他引:1  
P C Holland 《Cognition》1990,37(1-2):105-131
In a typical Pavlovian conditioning experiment, a relatively insignificant event, the conditioned stimulus (CS), is paired with a biologically more meaningful event, the unconditioned stimulus (US). As a consequence of those pairings, the CS is thought to acquire response characteristics of the US. In this article I describe experiments with rats that suggest that under some circumstances, the CS acquires control of perceptual processing of the US, in the absence of that US itself. I present three kinds of evidence for this surrogate processing, which I liken to imagery or hallucination: (1) CSs come to control specific, sensory-evaluative responses normally evoked only by the USs; (2) CSs can substitute for USs in the establishment of new learning about those USs themselves; (3) CSs can substitute for USs in the modulation of conditioning to other events, either overshadowing (interfering) or potentiating learning, in the same manner as the USs themselves. Finally, I compare these data with evidence for conditioned sensation and imagery in humans, and suggest that imagery may be a very basic process, evolutionarily derived from perceptual and conditioning processes adapted to deal with remote or absent objects.  相似文献   
990.
The responses given by highly hypnotizable, hypnotic subjects and those of unhypnotizable subjects who simulated hypnosis to questions of the type, "Do you mind telling me your name?" and "Do you mind standing up?" were contrasted. The purpose was to examine Erickson's (1980) assertion that literalism (answering "yes" or "no" verbally or nonverbally without any cognitive elaboration) is a marker of hypnotic "trance." Simulators exhibited a greater rate of literalism than hypnotic "virtuosos" (i.e., extreme scorers on both group and individual hypnotizability measures). Hypnotized subjects and nonhypnotized subjects approached in the campus library responded comparably. Because less than a third of hypnotic virtuosos responded literally, our results strongly refuted Erickson's assertion that literalism is a cognitive feature of hypnosis.  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