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   26161篇
  免费   920篇
  国内免费   281篇
  2020年   261篇
  2019年   264篇
  2018年   320篇
  2017年   356篇
  2016年   397篇
  2015年   313篇
  2014年   351篇
  2013年   1865篇
  2012年   672篇
  2011年   691篇
  2010年   476篇
  2009年   466篇
  2008年   654篇
  2007年   593篇
  2006年   535篇
  2005年   515篇
  2004年   455篇
  2003年   457篇
  2002年   474篇
  2001年   693篇
  2000年   679篇
  1999年   471篇
  1998年   246篇
  1992年   468篇
  1991年   454篇
  1990年   459篇
  1989年   461篇
  1988年   408篇
  1987年   422篇
  1986年   445篇
  1985年   486篇
  1984年   411篇
  1983年   381篇
  1982年   276篇
  1981年   314篇
  1979年   441篇
  1978年   322篇
  1977年   286篇
  1976年   276篇
  1975年   410篇
  1974年   461篇
  1973年   488篇
  1972年   411篇
  1971年   404篇
  1970年   380篇
  1969年   403篇
  1968年   493篇
  1967年   476篇
  1966年   453篇
  1958年   253篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The paper discusses regularisation of dualities. A given duality between (concrete) categories, e.g. a variety of algebras and a category of representation spaces, is lifted to a duality between the respective categories of semilattice representations in the category of algebras and the category of spaces. In particular, this gives duality for the regularisation of an irregular variety that has a duality. If the type of the variety includes constants, then the regularisation depends critically on the location or absence of constants within the defining identities. The role of schizophrenic objects is discussed, and a number of applications are given. Among these applications are different forms of regularisation of Priestley, Stone and Pontryagin dualities.  相似文献   
992.
The purpose of this study was to investigate the degree to which age-related and individual differences in children’s working memory (WM) are due to a general or task-specific capacity system. Experiment 1 correlated children’s (N=146; age range 5–19 years) verbal and visual-spatial working memory performance with various intelligence and achievement measures. The results supporting a general system were that (1) visual-spatial and verbal WM measures were significantly intercorrelated with and without age partialed out and (2) both verbal and visual-spatial WM measures were significantly correlated with diverse achievement and intelligence measures. Experiment 2 compared three age groups (N=192; 7-, 10-, and 13-year-olds) on working-memory performance tasks under initial, enhanced (cued), and maintenance conditions. The results supporting a general capacity system were that (1) age-related performance differences in WM were found on all conditions and not isolated to specific processes, (2) the maintenance measures (high-load condition) predicted the variance better in age-related performance than process measures, and (3) although individual differences in WM performance reflected two independent operations, these operations produced similar correlations to achievement within age groups. Overall, the results support a general capacity explanation of age-related and individual differences in children’s WM performance.  相似文献   
993.
Two experiments examined the generalizability of the effects of word length and phonological similarity with visual and auditory presentation in immediate verbal serial ordered recall. In Experiment 1, data were collected from 251 adult volunteers drawn from a broad cross-section of the normal population. Word length and phonological similarity in both presentation modes significantly influenced the group means. However, 43% of the subjects failed to show at least one of the effects, and the likelihood that effects appeared was highly correlated with verbal memory span. In Experiment 2, 40 subjects of the original sample were retested, 20 of whom had failed to show one or more effects in Experiment 1. Whether or not an effect had appeared for individual subjects on the first test session was a poor predictor of whether the effect would appear on retest. Finally, an analysis of subject reports demonstrated that the patterns of experimental data could be accounted for in part by the strategies that subjects reported using, and the effect of strategy was independent of the effect of span. The implications of these findings for theories of verbal short-term memory are discussed.  相似文献   
994.
We present three experiments designed to investigate the role of prosody during sentence processing. The first investigated the question of whether an utterance's prosodic contour influences its comprehension on-line. We spliced the beginning and end portions of direct object and embedded clause sentences and observed the consequent effects on comprehension using a dual-task procedure to measure processing load. Our second experiment sought to determine-whether the constituent structure of these sentences could be reliably predicted using prosodic information. We found that the duration and F0 contour associated with the main-clause verb and the following NP reliably distinguished between the direct object and embedded clause constructions. In the final experiment, we manipulated the duration of the main-clause verb and found that subjects used this information to guide their initial parse during on-line sentence comprehension. The need for a model of sentence processing that addresses the use of prosodic information is discussed.The work reported in this paper was supported in part by NTH grant DC00494.  相似文献   
995.
A contrived play group procedure was utilized to examine the behavioral and social-cognitive correlates of reactive aggression, proactive aggression, and victimization via peers. Eleven play groups, each of which consisted of six familiar African-American 8-year-old boys, met for 45-min sessions on five consecutive days. Social-cognitive interviews were conducted following the second and fourth sessions. Play group interactions were videotaped and examined by trained observers. High rates of proactive aggression were associated with positive outcome expectancies for aggression/assertion, frequent displays of assertive social behavior, and low rates of submissive behavior. Reactive aggression was associated with hostile attributional tendencies and frequent victimization by peers. Victimization was associated with submissive behavior, hostile attributional bias, reactive aggression, and negative outcome expectations for aggression/assertion. These results demonstrate that there is a theoretically coherent and empirically distinct set of correlates associated with each of the examined aggression subtypes, and with victimization by peers.  相似文献   
996.
This experiment investigated the effects of three factors on performance appraisal ratings: self-appraisal information, appraisal purpose, and feedback target. Two hundred and three subjects rated a subordinate's performance on a clerical task subsequent to receiving either a high or low self-assessment. They were told they would provide performance feedback either to the experimenter (organizational agent) or their subordinate, and their ratings would be used either for an administrative decision or developmental feedback. Performance ratings were significantly higher when subjects received a favorable subordinate self-assessment than when self-assessments were unfavorable. A significant interaction was found between feedback target and the appraisal purpose. Implications for the use of self-appraisals in organizations were discussed.  相似文献   
997.
Three psychological theories of psychosis are described, each of which has standing in psychiatry. Defined by the terms projection, double bind, and possession, they initially appear to have little or nothing in common to explain psychosis, but converge at four points: (1) A high degree of anxiety precipitated by a dilemma or conflict perceived to be unsolvable by the person; (2) the anxiety triggers a shift from one thought or motive in the direction of its opposite, because the original was believed too antagonistic to the wishes of significant others; (3) the opposite, in order to remain opposite, requires that the original thought or motive be forgotten, (4) a singular means to produce and reinforce forgetting is the interposition of psychiatric symptoms. In psychiatry today treatment would fit more consistently with the three theories taken as a whole rather than any one, and a rationale for this viewpoint is elaborated.  相似文献   
998.
The health belief model was evaluated for its ability to predict perceived and actual dietary quality. The assessment relied upon data collected from 1,502 respondents by the US. Department of Agriculture in its 1991 Continuing Survey of Food Intakes by Individuals and the Diet and Health Knowledge Survey. The health belief model provided good prediction of perceived dietary quality, but provided moderate to weak prediction of 7 measures of actual dietary quality that were calculated from food intake records. Implications are suggested for using the health belief model to understand the determinants of dietary quality.  相似文献   
999.
In response to new theoretical conceptualizations (Raven, 1992, 1993), an instrument was developed to measure 11 bases of power, the original 6 French and Raven (1959; Raven, 1965) bases of power, with 3 of these further differentiated: reward (personal, impersonal), coercion (personal. impersonal), legitimate (position, reciprocity, equity, dependence), expert, referent, and information. In Study 1, 317 American student respondents rated the likelihood that each of these power bases contributed to a supervisor successfully influencing a subordinate in a series of hypothetical situations. The internal consistency of the items which made up the 11 power bases proved adequate. Factor analysis found 7 factors and 2 categories of bases: harsh and soft. In Study 2, which used 101 Israeli health workers, the earlier findings were generally supported. In addition, job satisfaction was found to be positively related to the attribution of soft bases to the supervisor.  相似文献   
1000.
A multiple baseline design was used to evaluate the effects of Van Houten and Thompson's (1976) explicit timing procedure on problem completion rates and accuracy levels in African-American third-grade students. During the explicit timing phase, students were told that they were being timed and were instructed to circle the last problem completed at each 1-min interval. Results showed that the explicit timing procedure increased problem completion rates. A decreasing trend in percentage of problems correct also occurred. Exploratory data analysis suggested that decreases in accuracy were not caused by the explicit timing procedure and did not occur in students who had attained high levels of preintervention accuracy. Discussion focuses on recommendations for educators who wish to use timing procedures to increase students' rates of accurate responding.  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