全文获取类型
收费全文 | 214775篇 |
免费 | 9028篇 |
国内免费 | 164篇 |
出版年
2020年 | 2809篇 |
2019年 | 3479篇 |
2018年 | 4009篇 |
2017年 | 4427篇 |
2016年 | 4964篇 |
2015年 | 3963篇 |
2014年 | 4821篇 |
2013年 | 23526篇 |
2012年 | 5947篇 |
2011年 | 5571篇 |
2010年 | 4528篇 |
2009年 | 5109篇 |
2008年 | 5511篇 |
2007年 | 5219篇 |
2006年 | 5335篇 |
2005年 | 5177篇 |
2004年 | 4663篇 |
2003年 | 4222篇 |
2002年 | 4096篇 |
2001年 | 5104篇 |
2000年 | 4862篇 |
1999年 | 4273篇 |
1998年 | 3014篇 |
1997年 | 2816篇 |
1996年 | 2711篇 |
1995年 | 2533篇 |
1994年 | 2487篇 |
1993年 | 2451篇 |
1992年 | 3574篇 |
1991年 | 3414篇 |
1990年 | 3253篇 |
1989年 | 3071篇 |
1988年 | 3026篇 |
1987年 | 3010篇 |
1986年 | 3049篇 |
1985年 | 3274篇 |
1984年 | 3087篇 |
1983年 | 2740篇 |
1982年 | 2567篇 |
1981年 | 2523篇 |
1980年 | 2350篇 |
1979年 | 2944篇 |
1978年 | 2548篇 |
1977年 | 2412篇 |
1976年 | 2253篇 |
1975年 | 2629篇 |
1974年 | 2759篇 |
1973年 | 2751篇 |
1972年 | 2313篇 |
1968年 | 2251篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
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
902.
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
903.
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
904.
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
905.
906.
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
907.
B A Maher T C Manschreck C C Weisstein M L Schneyer R Okunieff 《Perceptual and motor skills》1988,67(3):911-918
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
908.
Performance of two groups of youngsters, educable mentally retarded (CA 15-5; MA 11-4; IQ 74.3) and those of average ability (CA 10-5; MA 11-3; IQ 109.1) was compared for intentional and incidental visual memory as a function of cognitive level and color of the stimulus. Nonretarded subjects performed significantly better than the retarded ones of equal MA. Both groups performed better with a color than black-white card, and both groups did better on the tasks involving intentional rather than incidental memory. 相似文献
909.
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
910.
Individuals with stronger sex-role identities may be expected to show greater conformity to sex-typed behaviors. Proceeding from this assumption, the sex-role status and sex of students using different styles of carrying books were compared. This study also examined whether over-all hand preference or age were related to carrying styles or sex-role status. Subjects completed a questionnaire comprised of the 24-item Personal Attributes Questionnaire of Spence and Helmreich, a 6-item scale of hand preference and a self-rating of sex-role identity. Afterwards, each subject's carrying style was covertly observed and recorded. Most subjects carried their materials in a sex-typical way or in book bags (for which no sex-typed carrying styles were discovered). As in previous studies, men in this study scored higher than women on masculinity and androgyny and lower on femininity. Hand preference was not related to sex-role status. Carrying style was not significantly correlated with any of the predictor variables for men, perhaps because almost no variance in carrying style was observed among them. Women who used masculine carrying styles tended to be older, have greater instrumentality, and a more masculine identity. 相似文献