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   672篇
  免费   54篇
  国内免费   72篇
  2024年   3篇
  2023年   13篇
  2022年   14篇
  2021年   31篇
  2020年   34篇
  2019年   27篇
  2018年   39篇
  2017年   36篇
  2016年   36篇
  2015年   25篇
  2014年   25篇
  2013年   113篇
  2012年   15篇
  2011年   21篇
  2010年   10篇
  2009年   9篇
  2008年   23篇
  2007年   25篇
  2006年   29篇
  2005年   41篇
  2004年   26篇
  2003年   21篇
  2002年   19篇
  2001年   27篇
  2000年   17篇
  1999年   19篇
  1998年   7篇
  1997年   12篇
  1996年   7篇
  1995年   7篇
  1994年   6篇
  1993年   13篇
  1992年   11篇
  1991年   2篇
  1989年   4篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1980年   3篇
  1979年   2篇
  1978年   4篇
  1977年   4篇
  1976年   4篇
  1975年   1篇
排序方式: 共有798条查询结果,搜索用时 0 毫秒
81.
The influence of ferritic steel samples with different case-depths on the distortion behaviour of magnetic excitation voltage has been investigated. The systematic changes in the height and position of the peak and the trough on the ((dVE/dt) vs. VT) profile (distortion analysis of the magnetic excitation, DAME profile) reflect the difference in the magnetization process and hence the effect of distortion of VE in samples with different case-depths. This study shows the potential of this simple DAME method for evaluation of ferromagnetic steel components.  相似文献   
82.

As compared with conventional vaccine production systems, plant-made vaccines (PMVs) are said to enjoy a range of advantages including cost of production and ease of storage for distribution in developing countries. In this article, we introduce the science of PMV production, and address ethical issues associated with development and clinical testing of PMVs within three interrelated domains: PMVs as transgenic plants; PMVs as clinical research materials; and PMVs as agents of global health. We present three conclusions: first, while many of the ethical issues raised by PMVs are familiar, PMVs add a new dimension to old issues, and raise some novel issues for ethicists and policy-makers; secondly, it is premature to promise broad applicability of PMVs across the developing world without having demonstrated their feasibility; thirdly, in particular, proponents of PMVs as a solution to global health problems must, as a condition of the ethical conduct of their research, define the commercial feasibility of PMVs for distribution in the developing world.  相似文献   
83.
Abstract

High-stakes testing has emerged as a central feature of the educational landscape in primary and secondary schools in the United States. Despite this prominence, there is a paucity of guidance available to practitioners on how they can best make predictions about student performance based on available test data. While achievement gaps based on demographics are widely known, less commonly analyzed are differences in opportunities to learn. Results from the first group of students in Massachusetts required to take a state-created exam in order to graduate from high school indicated that both demographics and courses taken were significant predictors of performance. Recommendations for analyzing test data and for promoting more comprehensive and culturally responsive assessment and curriculum practices are offered.  相似文献   
84.
Abstract

Confirmatory factor analysis was employed to test the multidimensional structure of test anxiety. Starting with the traditional two-factor model, it was of interest whether additional dimensions could still be represented by a single higher-order factor of test anxiety or whether the additional dimensions represented correlates of test anxiety. The Revised Test Anxiety (RTA) scale and the German Test Anxiety Inventory (TAI-G) were combined collecting data from a binational sample of 218 American and 218 German university students. Considering the statistical and theoretical aspects of model fit, they indicated that a model consisting of three primary factors (worry, emotionality, and lack of confidence) fit the data best. While distraction and self-efficacy may be regarded as correlates of test anxiety, lack of confidence was substantiated as a component of test anxiety. Implications for the conceptualization of the content domain and hence area of test anxiety were discussed.  相似文献   
85.
Wason's standard 2-4-6 task requires discovery of a single rule and leads to around 20% solutions, whereas the dual goal (DG) version requires discovery of two rules and elevates solutions to over 60%. We report an experiment that aimed to discriminate between competing accounts of DG facilitation by manipulating the degree of complementarity between the to-be-discovered rules. Results indicated that perfect rule complementarity is not essential for task success, thereby undermining a key tenet of the goal complementarity account of DG facilitation. The triple heterogeneity account received a good degree of support since more varied triple exploration was associated with facilitatory DG conditions, in line with this account's prediction that task success is associated with the creative search of the problem space. The contrast class account (an extension of Oaksford & Chater's, 1994, iterative counterfactual model) was also corroborated in that the generation of descending triples was demonstrated to be the dominant predictor of DG success. We focus our discussion on conceptual ideas relating to the way in which iterative counterfactual testing and contrast class identification may work together to provide a powerful basis for effective hypothesis testing.  相似文献   
86.
ABSTRACT

This study examines age-associated changes in retrieval on a picture-naming task, phonemic and semantic fluency tasks, and the Homophone Meaning Generation Test (HMGT). The sample included 152 Hebrew-speaking adults, half young (mean age 22.75) and half old (mean age 76.05). Groups differed on the picture-naming task and on both verbal fluency tasks, but not on the HMGT. Age explained a greater share of the variance than did education level on these three tests, whereas the opposite pattern of results was seen on the HMGT. We suggest that age-related word finding difficulties are attenuated when performance allows for semantic rather than phonological access.  相似文献   
87.
The present study examined the associations between mothers' and fathers' psychological control, socioeconomic status (SES) and their role in parents' educational aspirations for their adolescent children. Moreover, we examined to what extent SES and psychological control predicted their child's grade point average (GPA) and educational aspirations. A total of 1,034 Finnish adolescents aged 15 to 16 and their parents (720 mothers, 542 fathers) were surveyed at the beginning of the last grade of compulsory school. The results showed that the use of psychological control was more common among parents with lower SES. Moreover, the lower parents' SES was and the more psychological control they imposed, the lower were their educational aspirations for their adolescent children and lower was their child's GPA. The impact of SES was partially mediated by psychological control. The effects were similar for mothers and fathers.  相似文献   
88.
When faced with two competing hypotheses, people sometimes prefer to look at multiple sources of information in support of one hypothesis rather than to establish the diagnostic value of a single piece of information for the two hypotheses. This is termed pseudodiagnostic reasoning and has often been understood to reflect, among other things, poor information search strategies. Past research suggests that diagnostic reasoning may be more easily fostered when participants seek data to help in the selection of one of two competing courses of action as opposed to situations where they seek data to help infer which of two competing hypotheses is true. In the experiment reported here, we provide the first empirical evidence demonstrating that manipulating the relevance of the feature for which participants initially receive information determines whether they will make a nominally diagnostic or pseudodiagnostic selection. The discussion of these findings focuses on implications for the ability to engage in diagnostic hypothesis testing.  相似文献   
89.
This article provides a detailed analysis of the intellectual research project of Wilhelm Mann, one of the pioneers of experimental and educational psychology in Chile. Mann's work has been the object of so little analysis that his intellectual influences and networks are not clearly known. We analyzed 338 intratext citations from 22 works by Wilhelm Mann published during the period 1904–1915. As a result, we obtained a mapping of his cooperation networks and used a quantitative approach to study the authors who most influenced his career, among whom were William Stern, Herbert Spencer, Wilhelm Wundt, Alfred Binet, and Ernst Meumann. Mann was closely connected to the international and contemporary advances and discussions of his time, despite the lack of infrastructure and difficulties in communication. Mann was the first psychologist to develop a long-term project in Chile that aimed to measure the individualities of Chilean students and their intellectual development.  相似文献   
90.
Characterizing diversity in beliefs is of paramount importance in empirical research on human behavior. In game theory, the focus is on the hypothesis formation. We present a data set with ideal properties for characterizing such diversity. The data consist of hypotheses on the empirical distribution of opponent choices. Using nonparametric techniques, we identify modes in the data corresponding to subpopulations of behavioral types and find the statistical significance of these modes in the underlying population distribution.  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