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   63112篇
  免费   2613篇
  国内免费   26篇
  65751篇
  2020年   782篇
  2019年   913篇
  2018年   1305篇
  2017年   1310篇
  2016年   1373篇
  2015年   974篇
  2014年   1181篇
  2013年   5625篇
  2012年   2193篇
  2011年   2226篇
  2010年   1346篇
  2009年   1400篇
  2008年   1913篇
  2007年   1926篇
  2006年   1741篇
  2005年   1465篇
  2004年   1497篇
  2003年   1486篇
  2002年   1409篇
  2001年   2023篇
  2000年   1905篇
  1999年   1463篇
  1998年   707篇
  1997年   642篇
  1996年   695篇
  1995年   652篇
  1994年   621篇
  1993年   630篇
  1992年   1189篇
  1991年   1099篇
  1990年   1066篇
  1989年   1028篇
  1988年   1005篇
  1987年   949篇
  1986年   930篇
  1985年   987篇
  1984年   826篇
  1983年   743篇
  1982年   571篇
  1979年   858篇
  1978年   658篇
  1977年   561篇
  1976年   574篇
  1975年   679篇
  1974年   754篇
  1973年   772篇
  1972年   658篇
  1971年   599篇
  1968年   651篇
  1967年   562篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
991.
In an investigation of the effects of simulated stuttering on listener recall, a presentation was varied on two factors: degree of stuttering (mild or severe) and information value of stuttered words (low or high). A control presentation featuring non-stuttered speech also was prepared. Five groups of 16 subjects were randomly assigned to, and participated in, one of the five listening conditions. Then they completed a 20-item recall test. A one-way analysis of variance revealed sognificant differences among the five conditions. Two-way analysis of variance disclosed no main effects. However, a significant interaction showed that recall was lowest in the severe stuttering-high information condition. The results are discussed in terms of attention to critical information.  相似文献   
992.
Aphasic and nonaphasic listeners' comprehension of main ideas and details within coherent and noncoherent narrative discourse was examined. Coherent paragraphs contained one topic to which all sentences in the paragraph related. Noncoherent paragraphs contained a change in topic with every third or fourth sentence. Each paragraph contained four main ideas and one or more details that related to each main idea. Listeners' responses to yes/no questions following each paragraph yielded the following results: (1) Nonaphasic listeners comprehended the paragraphs better than aphasic listeners. (2) Both aphasic and nonaphasic listeners comprehended main ideas better than they comprehended details. (3) Coherence did not affect comprehension of main ideas for either group. (4) Coherence did not affect comprehension of details by nonaphasic subjects. (5) Coherence affected comprehension of details by aphasic subjects, and their comprehension of details in coherent paragraphs was worse than their comprehension of details in noncoherent paragraphs. There was no significant correlation between Token Test scores and measures of paragraph comprehension.  相似文献   
993.
The major theories and research approaches as to the etiology and development of stuttering are reviewed from a historical perspective. Findings are drawn from different sources indicating that language deficits are an initial contributing factor and a continuing component of this disorder. Those subsets of children which constitute high-risk groups are identified. It is suggested that researchers begin investigating the underlying organic bases of stuttering and its relationship to stages of language development. Finally, clinicians are encouraged to employ a therapy program that is concerned with all areas of language, rather than emphasizing treating only the symptoms of stuttering behavior.  相似文献   
994.
A mathematical model is developed to describe sequential effects in two-choice reaction time experiments with a short response-stimulus interval. Evidence is briefly discussed that in conditions with short response-stimulus intervals, automatic aftereffects dominate sequential effects, and the influence of subjective expectancy can be neglected. In these conditions the model premises three components of automatic aftereffects--facilitation, inhibition, and noise, with a common decay factor. Influence of response-stimulus interval and practice on sequential effects are examined and related to parameter changes in the proposed single-decay model. The decrease of automatic aftereffects with increasing response-stimulus interval is primarily ascribed to an increasing decay factor. The parameter representation of the model also clarifies the issue of the disappearance of automatic aftereffects with practice. It shows a gradual fading of inhibition in the initial stages of practice, together with a slower decrease of the facilitation effect. The single-decay model provides a satisfactory explanation for the processes involved in compatible two-choice reaction time with short response-stimulus interval.  相似文献   
995.
Learned helplessness theory predicts that animals exposed to inescapable shock acquire an expectancy of response-reinforcer independence, which proactively interferes with learning of response-reinforcer dependence. The theory also predicts that this expectancy can increase sensitivity to subsequent instances of response-reinforcer independence. These experiments test the latter prediction in a paradigm that minimizes the confounding effects of shock-induced activity deficits. Rats were trained to respond for food, then given either escapable, inescapable, or no shock. Subsequently, they received two sessions of response-contingent food followed by sessions of noncontingent food deliveries. During this phase, inescapably shocked animals decreased responding faster than did controls. Experiment 2 replicated this finding with a different schedule of food delivery and a procedure that more directly minimized the possibility that the outcome is due to either direct or indirect shock-induced activity changes. These results support the prediction that uncontrollable aversive events can increase an animal's sensitivity to noncontingent response-reinforcer relationships.  相似文献   
996.
997.
998.
The present study explored individual differences in performance of a geometric analogies task. Whereas past studies employed true/false or two-alternative items, the present research included four-alternative items and studied eye movements and confidence judgements for each item performance as well as latency and error. Item difficulty proved to be a function of an interaction between the number of response alternatives and the number of elements in items, especially for subjects lower in fluid-analytic reasoning ability. Results were interpreted using two hypothesized performance strategies: constructive matching and response elimination. The less efficient of these, response elimination, seemed to be used more by lower ability subjects on more difficult items. While two previous theories resemble one or the other of these strategies, neither alone seems to capture the complexity of adaptive problem solving. It appears that a comprehensive theory should incorporate strategy shifting as a function of item difficulty and subject ability.Componential models, based in part on past research, revealed that a justification component was activated and deactivated depending upon the nature of the analogy being solved. In addition, two new components, spatial inference and spatial application, were identified as important on some items, suggesting that different geometric analogy items invoke different cognitive processing components. Thus, a comprehensive theory should also describe component activation and deactivation.  相似文献   
999.
The purpose of this study was to clarify contradictory findings concerning the social status of aggressive youngsters. This was undertaken by dividing kindergarten boys into either Aggressive [A] or Aggressive/Withdrawn [A/W] groups, as proposed by Ledingham [1981]. Both groups were found to be high on peer-nominated rejection, but the A group was also high on peer-nominated popularity while the A/W group was low. Similarly, both groups were observed to be high in negative peer interactions, but the A group was also high in positive interactions. It was noted that valuable information regarding the social status and social behavior of aggressive youngsters would be lost if such subgrouping is not undertaken. The relationship between Ledingham's categorizations and others reported in the literature was discussed.This research was supported in part by NIH grant No. 32992 to the first author.  相似文献   
1000.
Mixed hyperactive/reading-disabled children, selected from a large sample of hyperactive children, were compared to pure hyperactive children on demographic, behavioral, and neuropsychological measures. Children in the Mixed group were reading-disabled relative to age and IQ; those in the Pure group had achievement scores that were average relative to age and IQ. The Mixed group was significantly older than the Pure group; there were no differences in gender, race, or socioeconomic status. Behaviorally, the groups did not differ significantly on teacher ratings or on psychiatric ratings of aggression. The Mixed group had a significantly higher Performance IQ, whereas the Pure group had a significantly higher Verbal IQ and performed better on measures of cognitive impulsivity. Several other measures failed to distinguish the groups. The data give minimal support to the notion that pure hyperactive and mixed hyperative/reading-disabled children constitute distinct subgroups of Attention Deficit Disorder with Hyperactivity.This research was supported in part by Mental Health Clinical Research Grant MH-30906 and by U. S. Public Health Service Grant MH-18579.  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