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   55888篇
  免费   2271篇
  国内免费   26篇
  2020年   641篇
  2019年   737篇
  2018年   1077篇
  2017年   1093篇
  2016年   1123篇
  2015年   772篇
  2014年   993篇
  2013年   4257篇
  2012年   1774篇
  2011年   1819篇
  2010年   1112篇
  2009年   1149篇
  2008年   1622篇
  2007年   1646篇
  2006年   1477篇
  2005年   1316篇
  2004年   1213篇
  2003年   1171篇
  2002年   1159篇
  2001年   1806篇
  2000年   1753篇
  1999年   1348篇
  1998年   583篇
  1997年   561篇
  1996年   513篇
  1995年   514篇
  1992年   1137篇
  1991年   999篇
  1990年   1102篇
  1989年   946篇
  1988年   958篇
  1987年   909篇
  1986年   931篇
  1985年   921篇
  1984年   796篇
  1983年   733篇
  1982年   539篇
  1979年   844篇
  1978年   622篇
  1977年   521篇
  1975年   705篇
  1974年   791篇
  1973年   833篇
  1972年   637篇
  1971年   598篇
  1970年   533篇
  1969年   593篇
  1968年   716篇
  1967年   642篇
  1966年   603篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
251.
252.
A general model is developed for the analysis of multivariate multilevel data structures. Special cases of the model include repeated measures designs, multiple matrix samples, multilevel latent variable models, multiple time series, and variance and covariance component models.We would like to acknowledge the helpful comments of Ruth Silver. We also wish to thank the referees for helping to clarify the paper. This work was partly carried out with research funds provided by the Economic and Social Research Council (U.K.).  相似文献   
253.
Human motor learning is often measured by error scores. The convention of using mean absolute error, mean constant error, and variable error shows lack of desirable parsimony and interpretability. This paper provides the background of error measurement and states criticisms of conventional methodology. A parsimonious model of error analysis is provided, along with operationalized interpretations and implications for motor learning. Teaching, interpreting, and using error scores in research may be simplified and facilitated with the model.  相似文献   
254.
Body-frame size is an important factor in determining an optimal body weight for a given height. Previous studies have indicated that many individuals incorrectly estimate their body-frame size, and, as a result, incorrectly assess their ideal weight. The present study investigated the accuracy of estimation of body-frame size as a function of sex and actual frame size. The subjects were 66 men and 52 women participating in a community adult fitness program. Data indicated that medium-framed individuals were the most accurate in their estimations of body-frame size. Also, women were twice as likely to be accurate as were men. These results are interpreted to mean that most people assume they are medium-framed and that there is a sex difference in the way body-frame size is estimated.  相似文献   
255.
In this pilot study, 20 middle-school-age children classified as emotionally handicapped were administered Forms L and M of the Peabody Picture Vocabulary Test--Revised in test-retest fashion. Pearson correlations for Form L were .90, for Form M, .69, and these dependent correlations were significantly different from each other. As triennial school psychological evaluations typically contain tests which have been administered previously, e.g., WISC-R, WRAT-R, we suggest that psychologists use caution when using Form M to test or retest the receptive vocabulary of emotionally handicapped or disturbed middle-school-age children.  相似文献   
256.
257.
This research investigated the buffering role of social support in the relationship of work load to both tension-anxiety and coping for police radio dispatchers ( N = 60). Each dispatcher was observed throughout an entire 8-hour work shift by a trained observer. Objective load consisted of the hourly rate of incoming telephone calls, police radio transmissions, and face-to-face or written communications from superiors, co-workers, and others. At the end of each shift, measures were taken of dispatchers' perceived load, felt tension-anxiety, and coping actions. Hierarchical regression revealed that support from superiors moderated the effects of both objective and perceived loads; no main effects of support were found. Statistically significant interactions confirmed the hypothesized buffering role of support: under high perceived load, dispatchers with high social support engaged in more coping actions and felt less tension-anxiety than did low-support dispatchers. No differences were found when perceived load was low. Support also buffered effects of objective load on tension-anxiety but not on coping.  相似文献   
258.
This report examines two methodologic concerns pertaining to use of the cloze procedure in studying the predictability of schizophrenic speech, scoring criteria and raters' education (at or below college level). We find that two strategies for scoring the predictions of raters, one requiring the exact word, the other permitting a reasonable synonym, do not appear to differ in distinguishing groups of patients. The accuracy of raters' guessing is, however, correlated with raters' education: the more educated the rater, the more accurate the guessing. Thought-disordered schizophrenic speech is significantly less predictable than that of nonthought-disordered schizophrenics and normal controls when scored by less educated raters. These differences diminish when more highly educated raters are used. We conclude that raters' education can influence the sensitivity of cloze analysis.  相似文献   
259.
Light-eyed individuals generally perform better at self-paced activities while dark-eyed individuals perform better at reactive activities. Using multiple regression it was found that dark-eyed students hit a target with a frisbee more times than did light-eyed students.  相似文献   
260.
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