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   793篇
  免费   113篇
  国内免费   31篇
  937篇
  2025年   3篇
  2024年   11篇
  2023年   11篇
  2022年   12篇
  2021年   19篇
  2020年   31篇
  2019年   33篇
  2018年   24篇
  2017年   31篇
  2016年   39篇
  2015年   26篇
  2014年   34篇
  2013年   95篇
  2012年   30篇
  2011年   33篇
  2010年   26篇
  2009年   43篇
  2008年   46篇
  2007年   52篇
  2006年   46篇
  2005年   57篇
  2004年   33篇
  2003年   35篇
  2002年   30篇
  2001年   23篇
  2000年   13篇
  1999年   13篇
  1998年   14篇
  1997年   6篇
  1996年   6篇
  1995年   8篇
  1994年   7篇
  1993年   3篇
  1992年   9篇
  1991年   2篇
  1990年   7篇
  1989年   3篇
  1988年   5篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1982年   1篇
  1980年   4篇
  1979年   3篇
  1978年   1篇
  1976年   3篇
排序方式: 共有937条查询结果,搜索用时 0 毫秒
91.
    
The acceptability of sentences in natural language is constrained not only grammaticality, but also by the relationship between what is being conveyed and such factors as context and the beliefs of interlocutors. In many languages the critical element in a sentence (its focus) must be given grammatical prominence. There are different accounts of the nature of focus marking. Some researchers treat it as the grammatical realization of a potentially arbitrary feature of universal grammar and do not provide an explicit account of its origins; others have argued, however, that focus marking is a (grammaticalized) functional solution to the problem of efficiently transmitting information via a noisy channel. By adding redundancy to highlight critical elements in particular, focus protects key parts of the message from noise. If this information‐theoretic account is true, then we should expect focus‐like behavior to emerge even in non‐linguistic communication systems given sufficient noise and pressures for efficiency. We tested this in an experiment in which participants played a simple communication game in which they had to click cells on a grid to communicate one of two line figures drawn across the grid. We manipulated the noise, available time, and required effort, and measured patterns of redundancy. Because the lines in many cases overlapped, meaning that only some parts of each line could be used to distinguish it from the other, we were able to compare the extent to which effort was expended on adding redundancy to critical (non‐overlapping) and non‐critical (overlapping) parts of the message. The results supported the information‐theoretic account of focus and shed light on the emergence of information structure in language.  相似文献   
92.
93.
    
ABSTRACT

The Purpose in Life Scale was designed to provide a 12-item unidimensional measure of purpose in life employing a five-point Likert rating for each item. The present study supports the psychometric properties of the Italian translation of this instrument among 155 Catholic priests (mean age?=?46 years, SD?=?12.16). Internal consistency reliability generated an alpha coefficient of .90. The first factor generated by principal component analysis accounted for 49.5% of variance. Concurrent validity against the Purpose in Life Test was supported by a correlation of .63. Construct validity was supported by a correlation of .54 with the Satisfaction in Ministry Scale and by a correlation of ?.51 with the Scale of Emotional Exhaustion in Ministry. These properties commend the scale for future use among Catholic priests.  相似文献   
94.
    
Robust evidence of the deleterious effects of poverty on children's academic achievement has generated considerable interest in the neural mechanisms underlying these associations. In studies of specific neurocognitive skills, researchers have found pronounced socioeconomic disparities in children's language and executive function (EF) skills. In this article, we review research linking socioeconomic factors (e.g., family income, parental education) with children's brain structure and function, focusing on the neural systems involved in language and EF. Then, we cover the potential mediators of these associations, developmental timing, and strategies for prevention and intervention. To complement research at the behavioral level, we conclude with recommendations for integrating measures of the developing brain into this ongoing work.  相似文献   
95.
96.
    
The mathematical connection between canonical correlation analysis (CCA) and covariance structure analysis was first discussed through the Multiple Indicators and Multiple Causes (MIMIC) approach. However, the MIMIC approach has several technical and practical challenges. To address these challenges, a comprehensive COSAN modeling approach is proposed. Specifically, we define four COSAN-CCA models to correspond with four possible combinations of the data to be analyzed and the unique parameters to be estimated. In terms of the data, one can analyze either the unstandardized or standardized variables. In terms of the unique parameters, one can estimate either the weights or loadings. Besides the unique parameters of each COSAN-CCA model, all four COSAN-CCA models also estimate the canonical correlations as their common parameters. Taken together, the four COSAN-CCA models provide the correct point estimates and standard error estimates for all commonly used CCA parameters. Two numeric examples are used to compare the standard error estimates obtained from the MIMIC approach and the COSAN modeling approach. Moreover, the standard error estimates from the COSAN modeling approach are validated by a simulation study and the asymptotic theory. Finally, software implementation and future extensions are discussed.  相似文献   
97.
    
Increasing numbers of children raised by grandparents are students in schools. Their substitute family structure and precursors to the emergence of this family structure have implications for the children's school performance. Research suggests teachers view these children as at risk for difficult school functioning. The aforementioned judgment is problematic because teacher expectations, attributions, and biases are associated with stereotype threat that impacts student performance adversely. The author compares children raised by grandparents with children raised by parents and foster parents. The author examines the children's perceptions of their teachers' views of their school performance. He also examines the children's general feelings about school. Participants in the study were 6,550 students in Grades 6–8 from the nationally representative Health Behaviour in School-aged Children survey. Nonparametric statistical analyses reveal children raised by grandparents believe teachers' view their school performance negatively when compared with children living with both parents. Strategies are described to improve the children's performance in school and to foster favorable teacher perceptions.  相似文献   
98.
    
Using data from three samples and more than 1000 participants, this study have examined the psychometric properties of the Driver Behaviour Questionnaire (DBQ) in three countries from South-East Europe. Differences in driving behaviour between countries were also investigated. Exploratory factor analysis results supported the distinction between errors and violations in all three countries. Furthermore, the positive associations of both errors and violations with self-reported traffic accidents were also consistent in all three samples. In terms of differences in driving behaviour, Romanian drivers scored higher on many error and violation items in comparison to the other two countries. Also, speeding violations were the most common violations in all three countries. Overall, our results provide further support for using the DBQ to measure aberrant (i.e. errors and violations) driver behaviour.  相似文献   
99.
    
Collecting samples is a challenging task for face recognition, especially for some real-world applications such as law enhancement and ID card identification, where there is usually single sample per person (SSPS) used to train a face recognition system. To extract discriminative features from the small size samples, in this paper we propose virtual samples via bidirectional feature selection with global and local structure preservation (VS-BFS-GL) to augment the number of training samples. In VS-BFS-GL, bidirectional feature selection is developed, which introduces L2,1 norm to explore the face variations from both horizontal and vertical directions. Further, to include more variations in the virtual images, the global structure information and sample-specified local structure information of the SSPP training set are considered. By integrating bidirectional feature selection, global and local structure, the limited training samples are fully utilized and more knowledge are mined. To further improve the effectiveness of VS-BFS-GL, an auxiliary database containing different face variations can be used to explore the local structure information. We extensively evaluated the proposed approach on AR and FERET database. The promising recognition results demonstrate that VS-BFS-GL is robust to expression, pose and partial occlusion variations in the faces.  相似文献   
100.
    
The gain–loss model (GaLoM) is a formal model for assessing knowledge and learning. In its original formulation, the GaLoM assumes independence among the skills. Such an assumption is not reasonable in several domains, in which some preliminary knowledge is the foundation for other knowledge. This paper presents an extension of the GaLoM to the case in which the skills are not independent, and the dependence relation among them is described by a well‐graded competence space. The probability of mastering skill s at the pretest is conditional on the presence of all skills on which s depends. The probabilities of gaining or losing skill s when moving from pretest to posttest are conditional on the mastery of s at the pretest, and on the presence at the posttest of all skills on which s depends. Two formulations of the model are presented, in which the learning path is allowed to change from pretest to posttest or not. A simulation study shows that models based on the true competence space obtain a better fit than models based on false competence spaces, and are also characterized by a higher assessment accuracy. An empirical application shows that models based on pedagogically sound assumptions about the dependencies among the skills obtain a better fit than models assuming independence among the skills.  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