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   207360篇
  免费   8895篇
  国内免费   162篇
  2020年   2821篇
  2019年   3495篇
  2018年   3990篇
  2017年   4409篇
  2016年   4950篇
  2015年   3983篇
  2014年   4848篇
  2013年   23616篇
  2012年   5805篇
  2011年   5352篇
  2010年   4467篇
  2009年   5081篇
  2008年   5322篇
  2007年   5021篇
  2006年   5224篇
  2005年   5037篇
  2004年   4522篇
  2003年   4085篇
  2002年   3938篇
  2001年   4857篇
  2000年   4661篇
  1999年   4143篇
  1998年   2994篇
  1997年   2800篇
  1996年   2696篇
  1995年   2532篇
  1994年   2479篇
  1993年   2444篇
  1992年   3426篇
  1991年   3257篇
  1990年   3109篇
  1989年   2907篇
  1988年   2900篇
  1987年   2851篇
  1986年   2893篇
  1985年   3103篇
  1984年   2973篇
  1983年   2664篇
  1982年   2530篇
  1981年   2479篇
  1980年   2323篇
  1979年   2800篇
  1978年   2468篇
  1977年   2344篇
  1976年   2187篇
  1975年   2482篇
  1974年   2580篇
  1973年   2535篇
  1972年   2100篇
  1968年   1988篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
861.
862.
863.
864.
865.
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   
866.
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   
867.
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   
868.
Cutoff scores are used in a variety of settings to help managers make personnel decisions. Although cutoff scores are used widely, information about their derivation and appropriate use is scattered in the legal, psychometric, and professional literatures. The purpose of this paper is to analyze critically and to integrate these diverse literatures, to summarize what is known and what is unknown about the use and misuse of cutoff scores. Alternative methods are examined in relation to legal precedents set by the courts, to psychometric principles, and to the various sets of professional guidelines. Directions for future research are suggested, and we conclude with a set of recommendations regarding acceptable professional practice in this area.  相似文献   
869.
870.
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   
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