全文获取类型
收费全文 | 103225篇 |
免费 | 4241篇 |
国内免费 | 39篇 |
专业分类
107505篇 |
出版年
2020年 | 1035篇 |
2019年 | 1255篇 |
2018年 | 1753篇 |
2017年 | 1768篇 |
2016年 | 1923篇 |
2015年 | 1354篇 |
2014年 | 1646篇 |
2013年 | 7584篇 |
2012年 | 3029篇 |
2011年 | 3216篇 |
2010年 | 1996篇 |
2009年 | 1978篇 |
2008年 | 2852篇 |
2007年 | 2846篇 |
2006年 | 2592篇 |
2005年 | 2329篇 |
2004年 | 2193篇 |
2003年 | 2066篇 |
2002年 | 2129篇 |
2001年 | 3215篇 |
2000年 | 3148篇 |
1999年 | 2397篇 |
1998年 | 1177篇 |
1997年 | 1042篇 |
1996年 | 1022篇 |
1992年 | 2072篇 |
1991年 | 1947篇 |
1990年 | 1961篇 |
1989年 | 1788篇 |
1988年 | 1732篇 |
1987年 | 1678篇 |
1986年 | 1764篇 |
1985年 | 1867篇 |
1984年 | 1550篇 |
1983年 | 1403篇 |
1982年 | 1019篇 |
1981年 | 973篇 |
1979年 | 1619篇 |
1978年 | 1167篇 |
1977年 | 1001篇 |
1975年 | 1383篇 |
1974年 | 1560篇 |
1973年 | 1654篇 |
1972年 | 1402篇 |
1971年 | 1293篇 |
1970年 | 1192篇 |
1969年 | 1211篇 |
1968年 | 1585篇 |
1967年 | 1429篇 |
1966年 | 1289篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
841.
The incidence of secondary enuresis in 16 institutionalized conduct-disordered children was examined. In contrast to a control group of 16 noninstitutionalized conduct-disordered children, the former showed significantly more enuretic behaviour. Also, enuresis began within 6 mo. of the children's separation from their families, suggesting this problem is very likely related to the emotional trauma surrounding the change in living conditions. However, the small number of subjects limits further interpretation of the findings. 相似文献
842.
As more children with cancer survive, the importance of facilitating school reintegration as a part of maximizing the quality of life has become evident. Workshops have been presented to school personnel to acquaint them with the issues facing cancer patients and their families, but there are gaps in our knowledge of what school personnel really need or want to know. In this study, 18 teachers of children with cancer and 15 teachers with no prior contact with students with cancer completed a questionnaire designed to assess needs, beliefs, and priorities with regard to working with cancer patients in the classroom. Significant findings included: (a) a consensus that a certain core of information about medical/psychological issues would be useful, and presentation of such information by psychologists and medical personnel working with such families would be optimal; (b) teachers having cancer patients as students were less likely to see the adaptation of siblings as an important issue; (c) teachers associated working with a student with cancer with less stress and demands on their time than predictable from previous studies; and (d) cancer patients as a whole were rated as having fewer behavioral, emotional, and learning problems than randomly selected students without a major illness, suggesting a "halo effect" or contradiction of some literature. Preliminary findings are detailed and implications are discussed for those attempting to help teachers facilitate students' adjustment to school following diagnosis and treatment of cancer. 相似文献
843.
19 pairs of third grade children from intact and single-parent families matched for sex, intellectual ability, and academic achievement were administered a brief self-concept measure. Teachers and parents rated the students' self-concept on similar measures. There were no significant differences in scores between the groups; however, within each group the teachers and parents consistently overestimated students' self-esteem. 相似文献
844.
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
845.
This experiment assessed the efficacy of proprioceptive and visual information for the performance of "vertical position" by synchronized swimmers. Three skill groups of 5 senior, 5 intermediate, and 5 novice synchronized swimmers performed 40 vertical positions under four conditions. The conditions were: self-initiated with and without vision, and following experimenter perturbation, with and without vision. The dependent measure was degrees of error from true vertical. Analysis indicated that either proprioception or proprioception and vision may be used in performing vertical positions. A significant main effect was found among skill groups. 相似文献
846.
To assess temporal variations in the perception of "phasic" heat pain stimuli a psychophysical tracking procedure was developed that enables repeated assessment of the pain threshold at short intervals. This "double-tracking" procedure produces two tracking curves simultaneously, one that approaches the pain threshold gradually from above, the other from below. The threshold for phasic heat pain was measured in 80 tracking trials with stimuli at temperatures near the pain threshold. Concurrently, the threshold for "tonic" heat pain was determined after every 20 tracking trials with a stimulus adjustment procedure. Eleven healthy subjects (age: 26.4 yr. +/- 6.0) participated in 2 sessions each. Phasic stimulation near the pain threshold did not produce any trends in either of the two threshold measures. Hence there was no long-term adaptation or sensitization. However, there were random variations (random walks) in the tracking curves, which we interpret as resulting from a stochastic relationship between stimulus and sensation. In agreement with other reports, discrimination seemed to be better at painful than at nonpainful temperatures. 相似文献
847.
R Topp 《Perceptual and motor skills》1989,69(1):35-41
The purpose of this study was to determine whether test anxiety could be significantly reduced through regular practice of relaxation exercises or physical exercise. Test anxiety was assessed at pretest and posttest using the 37-item true-false Test Anxiety Questionnaire developed by Sarason. 47 undergraduate students self-selected to participate. The 9 subjects in the group who engaged in a nonmeditative relaxation exercise 3 times per week for 7 weeks showed a significant decline in test anxiety. The 16 subjects in a supervised aerobic dance class 3 times per week for 7 weeks improved their fitness and their test anxiety significantly declined. The 20 control subjects did not meet over the 7-week study ahd showed no significant change in test anxiety, fitness, or relaxation. 相似文献
848.
Dynamic attending and responses to time 总被引:6,自引:0,他引:6
849.
Cognitive change processes in psychotherapy 总被引:1,自引:0,他引:1
C R Brewin 《Psychological review》1989,96(3):379-394
Several types of cognitive-behavioral therapy are now practiced that use different sets of theoretical concepts and propose different kinds of change mechanisms. None, however, is directly grounded in experimental research in cognitive and social psychology, and few address basic issues such as the relevance of conscious versus nonconscious cognitive processes and the validity of the self-report data on which therapy depends. Put forward in this article is a model that describes the conscious and nonconscious processing of emotional stimuli and distinguishes between knowledge that is verbally accessible and knowledge that can only be recovered by exposure to situational cues. Also proposed are three mechanisms of cognitive change that involve altering verbally accessible knowledge, the accessibility of nonconscious situational memories, and self-regulatory strategies. These mechanisms are related to the current practices of behavioral and cognitive-behavioral therapists. 相似文献
850.
Visual search and stimulus similarity 总被引:50,自引:0,他引:50