全文获取类型
收费全文 | 23767篇 |
免费 | 883篇 |
国内免费 | 9篇 |
专业分类
24659篇 |
出版年
2019年 | 309篇 |
2018年 | 392篇 |
2017年 | 363篇 |
2016年 | 435篇 |
2015年 | 297篇 |
2014年 | 387篇 |
2013年 | 2053篇 |
2012年 | 695篇 |
2011年 | 761篇 |
2010年 | 471篇 |
2009年 | 534篇 |
2008年 | 688篇 |
2007年 | 756篇 |
2006年 | 697篇 |
2005年 | 599篇 |
2004年 | 622篇 |
2003年 | 630篇 |
2002年 | 602篇 |
2001年 | 562篇 |
2000年 | 616篇 |
1999年 | 475篇 |
1998年 | 307篇 |
1997年 | 272篇 |
1996年 | 274篇 |
1995年 | 288篇 |
1993年 | 260篇 |
1992年 | 378篇 |
1991年 | 377篇 |
1990年 | 371篇 |
1989年 | 356篇 |
1988年 | 352篇 |
1987年 | 332篇 |
1986年 | 329篇 |
1985年 | 349篇 |
1984年 | 302篇 |
1983年 | 318篇 |
1982年 | 261篇 |
1981年 | 244篇 |
1980年 | 260篇 |
1979年 | 343篇 |
1978年 | 322篇 |
1977年 | 252篇 |
1976年 | 264篇 |
1975年 | 308篇 |
1974年 | 336篇 |
1973年 | 351篇 |
1972年 | 282篇 |
1971年 | 252篇 |
1968年 | 288篇 |
1967年 | 273篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
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
53.
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
54.
S Martin K Housley H Mccoy P Greenhouse F Stigger M A Kenney S Shoffner V Fu M Korslund F G Ercanli-Huffman 《Perceptual and motor skills》1988,67(3):879-884
The Rosenberg Self-esteem Scale was administered to 550 14- and 16-yr.-old (+/- 6 mo.) girls. Self-esteem scores were categorized by weight and weight by height. Scores on the Quetelet Index for obesity were correlated with self-esteem scores. Mean self-esteem of the low- and middle-weight by height group was significantly higher than the mean of the high-weight by height group. In analyzing weight alone, the self-esteem of the middle-weight group was significantly higher than the self-esteem of the high-weight group. The correlation of the obesity index and self-esteem indicated that as weight increased self-esteem decreased. 相似文献
55.
S W?sser W Handrick F B Spencker W Braun 《Psychiatrie, Neurologie, und medizinische Psychologie》1988,40(2):95-101
Observations on three children with neurolisteriosis (one case of meningitis, two cases of meningoencephalitis, each Serovar 4 b), show that even after the neonatal period, listeriosis must not be ignored in the process of diagnosis and therapy. It is the bacteriological examination of the cerebrospinal fluid, together with the blood culture, and not clinical symptoms and serology that guarantee a timely diagnosis and therapy (ampicillin and gentamicin). 相似文献
56.
57.
58.
59.
This paper gives a method for determining a sample size that will achieve a prespecified bound on confidence interval width for the interrater agreement measure,. The same results can be used when a prespecified power is desired for testing hypotheses about the value of kappa. An example from the literature is used to illustrate the methods proposed here. 相似文献
60.
Jos M. F. ten Berge 《Psychometrika》1988,53(4):487-494
Van de Geer has reviewed various criteria for transforming two or more matrices to maximal agreement, subject to orthogonality constraints. The criteria have applications in the context of matching factor or configuration matrices and in the context of canonical correlation analysis for two or more matrices. The present paper summarizes and gives a unified treatment of fully general computational solutions for two of these criteria, Maxbet and Maxdiff. These solutions will be shown to encompass various well-known methods as special cases. It will be argued that the Maxdiff solution should be preferred to the Maxbet solution whenever the two criteria coincide. Horst's Maxcor method will be shown to lack the property of monotone convergence. Finally, simultaneous and successive versions of the Maxbet and Maxdiff solutions will be treated as special cases of a fully flexible approach where the columns of the rotation matrices are obtained in successive blocks.The author is obliged to Henk Kiers for computational assistance and helpful comments. 相似文献