全文获取类型
收费全文 | 55304篇 |
免费 | 1036篇 |
国内免费 | 8篇 |
专业分类
56348篇 |
出版年
2020年 | 561篇 |
2019年 | 653篇 |
2018年 | 845篇 |
2017年 | 867篇 |
2016年 | 996篇 |
2015年 | 700篇 |
2014年 | 829篇 |
2013年 | 4072篇 |
2012年 | 1552篇 |
2011年 | 1580篇 |
2010年 | 970篇 |
2009年 | 1031篇 |
2008年 | 1383篇 |
2007年 | 1332篇 |
2006年 | 1196篇 |
2005年 | 1078篇 |
2004年 | 1032篇 |
2003年 | 986篇 |
2002年 | 1028篇 |
2001年 | 1614篇 |
2000年 | 1603篇 |
1999年 | 1168篇 |
1998年 | 549篇 |
1997年 | 513篇 |
1992年 | 1028篇 |
1991年 | 991篇 |
1990年 | 958篇 |
1989年 | 938篇 |
1988年 | 899篇 |
1987年 | 848篇 |
1986年 | 880篇 |
1985年 | 961篇 |
1984年 | 795篇 |
1983年 | 733篇 |
1982年 | 548篇 |
1981年 | 565篇 |
1979年 | 861篇 |
1978年 | 620篇 |
1977年 | 566篇 |
1976年 | 567篇 |
1975年 | 733篇 |
1974年 | 853篇 |
1973年 | 902篇 |
1972年 | 761篇 |
1971年 | 714篇 |
1970年 | 658篇 |
1969年 | 698篇 |
1968年 | 854篇 |
1967年 | 782篇 |
1966年 | 748篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
972.
Although there were no significant differences in the single support phase of gait for 6 trainable mentally retarded boys (Mean age 9.6 yr.) and 6 nonretarded boys (Mean age 9.5 yr.), total gait time and time in double support were significantly different for the two groups, supporting previous research which showed gait was was deficient in trainable mentally retarded individuals. 相似文献
973.
This study was designed to determine the feasibility of using lingual vibrotactile stimulation to elicit an averaged evoked response and to investigate the effects of two supra-threshold intensity levels of lingual vibrotactile stimulation on the electro-cortical activity of the brain. The evoked responses were analyzed according to the amplitude of N1-P2 (in microvolts). Analysis indicates that the tongue can successfully be used as a stimulus site in the elicitation of an evoked response. The amplitudes of the evoked response elicited by 2 micrometers sensation level and 5 micrometers sensation level on the tongue are essentially the same. The relative difference between these levels is not sufficient to produce significant differences in the amplitudes of their respective evoked responses. 相似文献
974.
H. W. Leibowitz C. L. Shupert R. B. Post J. Dichgans 《Attention, perception & psychophysics》1983,34(2):131-134
The reported direction of autokinesis for naive observers is not biased by gaze deviations of 22.5 deg of arc. However, instructions to expect either “inward” or “outward” movement produce reports of autokinetic movement that are progressively biased in the expected direction. Instructions to expect “more” or “less” movement resulted in a decrease in the reported duration of apparent movement for the “less” group but no change for the “more” group. Response bias is not considered to play a role in these results. The results are discussed in terms of fixational bias and selective attention mechanisms of autokinesis. 相似文献
975.
H Klepel R D Koch P Krause 《Psychiatrie, Neurologie, und medizinische Psychologie》1983,35(8):467-470
The results of clinical, electroencephalographic and repeated computed tomographic examination of 14 children suffering from epileptic seizures in connection with the West and Lennox-Gastaud syndrome are analyzed and compared. Computed tomography yields little information regarding the etiology of such forms of epilepsy. Distinct clinical and electroencephalographic findings were accompanied by normal computed tomographic results in a large proportion of the cases. To avoid misinterpretation of computed tomographic findings and consequent prognostic errors in these epileptic cases it is necessary to take possible side effects of ACTH and corticosteroid treatment into account. At the climax of hormone treatment computed tomography revealed imposing changes in the form of generalized atrophy in 10 of the 14 children examined. These receded completely upon termination of hormone treatment. 相似文献
976.
977.
Beliefs about cancer, heart disease, and their victims 总被引:1,自引:0,他引:1
978.
Interpretations regarding the effects of exogenous and endogenous variables on endogenous variables in linear structural equation systems depend upon the convergence of a matrix power series. Convergence depends upon the eigenvalues of the structural coefficient matrix. The test for convergence developed by Jöreskog and Sörbom is shown to be only sufficient, not necessary and sufficient. 相似文献
979.
We assume that a judge's task is to categorize each ofN subjects into one ofr known classes. The design of primary interest is employed if the judge is presented withs groups, each containingr subjects, such that each group of sizer consists of exactly one subject of each of ther types. The probability distribution for the total number of correct choices is developed and used to test the null hypothesis that the judge is guessing in favor of the alternative that he or she is operating at a better than chance level. The power of the procedure is shown to be superior to two other procedures which appear in the literature.The authors are grateful for the suggestions of the referees and for computer funding provided by the Northeast Regional Data Center at the University of Florida. 相似文献
980.