全文获取类型
收费全文 | 176164篇 |
免费 | 7861篇 |
国内免费 | 162篇 |
专业分类
184187篇 |
出版年
2021年 | 1528篇 |
2020年 | 2859篇 |
2019年 | 3538篇 |
2018年 | 3629篇 |
2017年 | 4042篇 |
2016年 | 4750篇 |
2015年 | 3997篇 |
2014年 | 4899篇 |
2013年 | 23937篇 |
2012年 | 4713篇 |
2011年 | 3816篇 |
2010年 | 4025篇 |
2009年 | 4870篇 |
2008年 | 4087篇 |
2007年 | 3593篇 |
2006年 | 4239篇 |
2005年 | 4186篇 |
2004年 | 3658篇 |
2003年 | 3355篇 |
2002年 | 3138篇 |
2001年 | 3079篇 |
2000年 | 2962篇 |
1999年 | 3052篇 |
1998年 | 2860篇 |
1997年 | 2719篇 |
1996年 | 2625篇 |
1995年 | 2451篇 |
1994年 | 2419篇 |
1993年 | 2355篇 |
1992年 | 2539篇 |
1991年 | 2382篇 |
1990年 | 2251篇 |
1989年 | 2159篇 |
1988年 | 2149篇 |
1987年 | 2165篇 |
1986年 | 2157篇 |
1985年 | 2376篇 |
1984年 | 2537篇 |
1983年 | 2307篇 |
1982年 | 2396篇 |
1981年 | 2363篇 |
1980年 | 2204篇 |
1979年 | 2179篇 |
1978年 | 2189篇 |
1977年 | 2151篇 |
1976年 | 1961篇 |
1975年 | 1995篇 |
1974年 | 2090篇 |
1973年 | 1959篇 |
1972年 | 1505篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
This study investigated the perception of the direction of peripheral apparent motion as a function of stimulus location in the peripheral visual field, stimulus contrast, and the direction of the apparent motion. Results indicated that each of these independent variables was significant as a main effect while the interactions were not. 相似文献
912.
W F Gayton K L Cielinski W J Francis-Keniston J F Hearns 《Perceptual and motor skills》1989,68(1):317-318
The effect of prohibiting the use of a preshot routine on free-throw shooting in competitive situations was investigated. 25 male high school basketball players were instructed to attempt 50 free throws alternating in blocks of 10 between the use of their preshot routine and shooting without it. To make the situation competitive, subjects were run in groups of five and their performance was recorded on a large easel placed to the side of the free-throw line. A significantly larger number of baskets were made in the preshot routine condition than without the routine. A competitive situation led to a greater decrement in baskets than had been reported in 1986 by Lobmeyer and Wassermen during noncompetitive free-throw shooting. 相似文献
913.
914.
A quasi-nonmetric method for multidimensional scaling VIA an extended euclidean model 总被引:1,自引:0,他引:1
An Extended Two-Way Euclidean Multidimensional Scaling (MDS) model which assumes both common and specific dimensions is described and contrasted with the standard (Two-Way) MDS model. In this Extended Two-Way Euclidean model then stimuli (or other objects) are assumed to be characterized by coordinates onR common dimensions. In addition each stimulus is assumed to have a dimension (or dimensions) specific to it alone. The overall distance between objecti and objectj then is defined as the square root of the ordinary squared Euclidean distance plus terms denoting the specificity of each object. The specificity,s
j
, can be thought of as the sum of squares of coordinates on those dimensions specific to objecti, all of which have nonzero coordinatesonly for objecti. (In practice, we may think of there being just one such specific dimension for each object, as this situation is mathematically indistinguishable from the case in which there are more than one.)We further assume that
ij
=F(d
ij
) +e
ij
where
ij
is the proximity value (e.g., similarity or dissimilarity) of objectsi andj,d
ij
is the extended Euclidean distance defined above, whilee
ij
is an error term assumed i.i.d.N(0, 2).F is assumed either a linear function (in the metric case) or a monotone spline of specified form (in the quasi-nonmetric case). A numerical procedure alternating a modified Newton-Raphson algorithm with an algorithm for fitting an optimal monotone spline (or linear function) is used to secure maximum likelihood estimates of the paramstatistics) can be used to test hypotheses about the number of common dimensions, and/or the existence of specific (in addition toR common) dimensions.This approach is illustrated with applications to both artificial data and real data on judged similarity of nations. 相似文献
915.
Visual search and stimulus similarity 总被引:50,自引:0,他引:50
916.
Robert L. Beck 《Journal of Family Therapy》1989,11(3):231-241
This paper describes the use of concurrent individual and conjoint sessions in couples psychotherapy. The introduction of these individual interviews is seen as supporting the individual changes which must be made to effect change in the structure of the relationship. The benefits of this interventive scheme in dynamically oriented couples' treatment will be illustrated through the presentation of case examples. 相似文献
917.
I. Bennun 《Journal of Family Therapy》1989,11(3):243-255
Thirty-five families completed ratings describing their perceptions of their therapists. These ratings were then correlated with measures of outcome to assess whether there was a relationship between experiences of the therapist and treatment outcome. Further, the study addresses whether some family members' perceptions are more influential in affecting the course of treatment. The results showed that family members' perception of the therapist does have an impact on treatment outcome, but not all members affect the outcome equally. Further results and their implications are discussed. 相似文献
918.
Thomas C. Ryckman 《Synthese》1989,79(2):191-200
Examines the connections among believing, saying, and expressing in situations where the sentence used is a declarative sentence containing at least one proper name. Proposes a new way of understanding these connections. Develops an argument for the thesis that, although we typically believe the singular propositions expressed by our uses of name sentences, we rarely use such sentences because we believe those propositions. 相似文献
919.
920.