首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4340篇
  免费   524篇
  国内免费   221篇
  2024年   23篇
  2023年   112篇
  2022年   76篇
  2021年   151篇
  2020年   239篇
  2019年   261篇
  2018年   211篇
  2017年   234篇
  2016年   246篇
  2015年   181篇
  2014年   186篇
  2013年   535篇
  2012年   139篇
  2011年   171篇
  2010年   111篇
  2009年   173篇
  2008年   178篇
  2007年   176篇
  2006年   165篇
  2005年   159篇
  2004年   118篇
  2003年   110篇
  2002年   113篇
  2001年   107篇
  2000年   84篇
  1999年   91篇
  1998年   72篇
  1997年   54篇
  1996年   54篇
  1995年   51篇
  1994年   46篇
  1993年   54篇
  1992年   41篇
  1991年   40篇
  1990年   44篇
  1989年   24篇
  1988年   28篇
  1987年   25篇
  1986年   21篇
  1985年   20篇
  1984年   14篇
  1983年   12篇
  1982年   18篇
  1981年   12篇
  1980年   17篇
  1979年   17篇
  1978年   30篇
  1977年   19篇
  1976年   17篇
  1975年   3篇
排序方式: 共有5085条查询结果,搜索用时 15 毫秒
991.
We extended research on the role of noncontingent positive reinforcement following a functional analysis of attention-maintained self-injurious behavior to self-injury maintained by negative reinforcement in 2 young males with developmental disabilities. During a pretreatment functional analysis, each participant's self-injury was shown to be differentially sensitive to escape from instructional activities as negative reinforcement. During noncontingent escape, escape from learning activities was provided on a fixed-time schedule that was not influenced by the participant's behavior. One participant was also exposed to differential negative reinforcement of other behavior. During this condition, escape from instructional activities was provided contingent on the omission of self-injury for prespecified intervals. Results showed that the provision of escape, even when noncontingent, resulted in significant reductions in self-injury. These results are particularly interesting in light of the experimental history of noncontingent reinforcement as a control rather than as a therapeutic procedure. Noncontingent escape is discussed as a form of extinction that may be less likely than other forms of extinction to produce severe side effects.  相似文献   
992.
This study examined overlap between four basal reading programs and the phonetic analysis subtest of three standardized achievement measures. Raw scores, percentages of items correct, grade equivalents, and percentile scores were computed for a hypothetical student who had mastered all grapheme-phoneme correspondences taught at each grade level. The results indicated that (a) programs differed in the number and sequence of phonics skills taught; (b) percentile and grade-equivalent scores differed across programs at each grade level for a given test; and (c) the proportion of grade-equivalent scores falling at or above expected grade levels differed across tests for a given program (range of 29%–71%). The implications for selecting and interpreting standardized measures of reading decoding are discussed.  相似文献   
993.
The manner in which the conditional independence graph of a multiway contingency table effects the fitting and interpretation of the Goodman association model (RC) and of correspondence analysis (CA) is considered.Estimation of the row and column scores is presented in this context by developing a unified framework that includes both models. Incorporation of the conditional independence constraints inherent in the graph may lead to equal or additive scores for the corresponding marginal tables, depending on the topology of the graph. An example of doubly additive scores in the analysis of a Burt subtable is given.Thanks are due to anonymous referees who substantially improved the original draft of this paper.  相似文献   
994.
Monotonically convergent algorithms are described for maximizing six (constrained) functions of vectors x, or matricesX with columns x1, ..., x r . These functions are h1(x)= k (xA kx)(xC kx)–1, H1(X)= k tr (XA k X)(XC k X)–1, h1(X)= k l (x l A kx l ) (x l C kx l )–1 withX constrained to be columnwise orthonormal, h2(x)= k (xA kx)2(xC kx)–1 subject to xx=1, H2(X)= k tr(XA kX)(XAkX)(XCkX)–1 subject toXX=I, and h2(X)= k l (x l A kx l )2 (x l C kX l )–1 subject toXX=I. In these functions the matricesC k are assumed to be positive definite. The matricesA k can be arbitrary square matrices. The general formulation of the functions and the algorithms allows for application of the algorithms in various problems that arise in multivariate analysis. Several applications of the general algorithms are given. Specifically, algorithms are given for reciprocal principal components analysis, binormamin rotation, generalized discriminant analysis, variants of generalized principal components analysis, simple structure rotation for one of the latter variants, and set component analysis. For most of these methods the algorithms appear to be new, for the others the existing algorithms turn out to be special cases of the newly derived general algorithms.This research has been made possible by a fellowship from the Royal Netherlands Academy of Arts and Sciences to the author. The author is obliged to Jos ten Berge for stimulating this research and for helpful comments on an earlier version of this paper.  相似文献   
995.
The present study investigated the proximal constraints that determine perceptual unit formation under minimal stimulus conditions. Projections of three moving dots, which could form two possible two-dot configurations, were presented to naive observers. In a forced-choice situation, their task was to report which two-dot configuration was perceived as a distinct perceptual unit. The results showed that common motions (arbitrary translations and rigid rotations in the frontoparallel plane) have stronger grouping power as compared to different relative motions (expansions/contractions, or simultaneous expansions/contractions and deformations in the frontoparallel plane). It was found that proximal changes of distances between elements in two-dot structures reduce grouping power. Changes of proximal directions, however, did not affect unit formation in two-dot structures at all. The effect of vector algebraic combinations on grouping power in three-dot strutures was also investigated. Evidently, visual vector analysis splits up motion combinations into their constituents, and in come cases this contributes to additive effects.  相似文献   
996.
Both spouses of 100 married, heterosexual couples completed the Personal Authority in the Family System Questionnaire (PAFS-Q). A cluster analysis of the couples' scores on the four intimacy and fusion scales of the PAFS-Q produced four clusters that were meaningfully distinct in the patterns of differentiation of the wives and husbands. Couples comprising these clusters are described in terms of intergenerational theories of family interaction.This paper is based on the master's thesis of the first author submitted to the Graduate School of Texas Woman's University. A presentation based on this work was given at the 1988 annual convention of the Southwestern Psychological Association, Tulsa, Oklahoma. The authors thank Glenda Peters and Joe Natale for their contributions to the preparation of this paper. A more extensive report of the methodology and results of this study can be obtained from the second author.  相似文献   
997.
This analogue study sought to determine the relative effectiveness of different instructional methods for teaching problem solving skills to teachers-in-training. Three instructional conditions (didactic, didactic + modeling, and didactic + modeling with rehearsal/feedback) and a control condition were compared on measures of problem identification and problem analysis. Results indicated that the didactic + modeling and didactic + modeling with rehearsal/feedback conditions were superior to didactic training in teaching problem-solving skills. Discussed are possible explanations for differences between the instructional conditions, the implications of these findings, limitations of this study, and directions for further teacher-training research in problem solving.  相似文献   
998.
The purpose of this study was to develop an instrument for assessing maternal attitudes. Three photographs representing infants or mother-infant dyads were presented to 26 mothers in the second half of pregnancy and six months after birth. Nine mothers were clinical cases, seventeen mothers were nonpathological controls. Thirty-three semantic categories were used to code the mothers' responses to the pictures. Mothers' responses were coded independently by two researchers. The factor analysis of the codes yielded an ‘attraction to, vs rejection of, children’ factor. Compared with the control group, the mean factor score of the clinical group was significantly lower, i. e. reflected less attraction (p < 0.01). To study the relation between the attraction factor and the physical proximity of mothers and infants, 21 of these mother-infant dyads were videotaped in a semi-structured play interaction six months after birth. Recordings were coded independently by two researchers for various indices of proximity (spatial proximity, kisses, embraces, touches). The factor analysis of the codes yielded a factor contrasting distant vs close and tender interaction. A significant correlation was found between the attraction scores of pregnant women and the proximity scores of mother-infant interaction (r = 0.46; p < 0.05). These results suggest that this instrument is useful in assessing maternal attitudes of psychiatrically disturbed pregnant women and that maternal attitudes of pregnant women are significant predictors of physical proximity in motherinfant interaction at the end of the first semester.  相似文献   
999.
中学高年级学生作文能力结构特征的研究   总被引:5,自引:3,他引:2  
对490名高三学生的18个作文变量的测验资料,运用高阶因素分析法概括出中学高年级学生作文能力结构的三个群因素。第一个是作文能力的因素,它是作文认知活动的各种能力相互作用的一种协调发展程度。第二个是由词汇量、造句等能力组合成的词语能力,它是作文能力结构中的一个活跃因素。第三个是词汇量因素,它独立存在于一阶、二阶因素中,表明它是不同阶段认知活动的一个不可缺的因素。  相似文献   
1000.
Results of recent research have shown that noncontingent reinforcement (NCR) can be effective in reducing the frequency of behavior problems. In typical NCR applications, the reinforcer that is responsible for behavioral maintenance (as demonstrated through a functional analysis) no longer follows occurrences of the target behavior but instead is delivered according to a time-based schedule. Thus, it is unclear if NCR would be effective if the target behavior continued to be reinforced or if arbitrary reinforcers (i.e., those irrelevant to behavioral maintenance) were substituted for the maintaining reinforcers in the NCR procedure. In this study, 2 individuals whose self-injurious behavior (SIB) was maintained by positive reinforcement were exposed to conditions in which arbitrary and maintaining reinforcers were withheld and were delivered either contingently or noncontingently. Results indicated that noncontingent delivery of arbitrary reinforcers was effective in reducing SIB even though occurrences of SIB produced access to the maintaining reinforcer. These results suggest that (a) arbitrary reinforcers may sometimes be substituted for maintaining reinforcers, (b) an important component of NCR procedures is alteration of a behavior's establishing operation, and (c) NCR with arbitrary reinforcers might therefore be effective when maintaining reinforcers cannot be identified or withheld during the course of treatment.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号