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   3789篇
  免费   32篇
教育   2653篇
科学研究   318篇
各国文化   56篇
体育   344篇
综合类   2篇
文化理论   50篇
信息传播   398篇
  2022年   20篇
  2021年   37篇
  2020年   70篇
  2019年   108篇
  2018年   120篇
  2017年   113篇
  2016年   94篇
  2015年   64篇
  2014年   110篇
  2013年   862篇
  2012年   86篇
  2011年   95篇
  2010年   77篇
  2009年   78篇
  2008年   79篇
  2007年   74篇
  2006年   91篇
  2005年   82篇
  2004年   73篇
  2003年   71篇
  2002年   58篇
  2001年   48篇
  2000年   57篇
  1999年   53篇
  1998年   57篇
  1997年   47篇
  1996年   42篇
  1995年   37篇
  1994年   36篇
  1993年   41篇
  1992年   32篇
  1991年   41篇
  1990年   43篇
  1989年   43篇
  1988年   45篇
  1987年   43篇
  1986年   39篇
  1985年   32篇
  1984年   39篇
  1983年   44篇
  1982年   30篇
  1981年   23篇
  1980年   27篇
  1979年   42篇
  1978年   38篇
  1977年   30篇
  1976年   32篇
  1974年   24篇
  1973年   26篇
  1969年   19篇
排序方式: 共有3821条查询结果,搜索用时 15 毫秒
141.
As part of a large‐scale study of the ability of 94 secondary schools to promote academic achievement, case studies of six outlier schools were conducted and headteachers (principals) and their deputies were questioned about the processes of effectiveness. The analysis of their responses ‐ grouped by the performance of their school (measured by value added analyses of three years of public examination results) as effective, ineffective or mixed ‐ reveals considerable support for previously cited characteristics of effective schooling. Despite the limitations imposed by a reliance on the use of retrospective accounts, the study takes forward the field of school effectiveness in its search for generalisable findings and coherent theory.

  相似文献   
142.
Conclusion It seems reasonable to conclude that the impact of these projects has been extensive and that we have met our basic objectives regarding the improvement of science education for the target teachers and students. The long-term goal of improved scientific literacy of at least a part of the citizens of this country and world can only be assessed by some form of longitudinal study that is beyond the scope and funding for these projects. But our assessment of what has been accomplished in the short term efforts seems to indicate very positive gains in those areas of knowledge, confidence, and pedagogical capability that we believe will enable the participants to make contributions to the improvement of scientific literacy for the students with whom they work. In short, we believe we have had two successful and worthwhile programs that have been useful and effective.  相似文献   
143.
Objective:To review our experience of the treatment of bilateral primary spontaneous pneumothorax (PSP) by video-assisted thoracoscopic surgery (VATS). Materials and methods: Retrospective chart review was followed by an on-clinic or telephone interview. Patients were cared for by one thoracic surgeon in four medical centers or community hospitals in Northern and Central Taiwan. Thirteen patients with bilateral PSP underwent bilateral VATS simultaneously or sequentially from July 1994 to December 2005. Results: Twelve males and one female, with age ranging from 15 to 36 years (mean 23.1 years), were treated with VATS for bilateral PSP, under the indications of bilateral pneumothoracis simultaneously (n=4) or sequentially (n=9). The interval between the first and second contra-lateral VATS procedure for non-simultaneous PSP patients ranged from 7 d to 6 years. Eleven of 13 patients (84.6%) had prominent pulmonary bullae/blebs, and underwent bullae resection with mechanical or chemical pleurodesis. The mean operative time was (45.6±18.3) min (range 25-96 min) and (120.6±28.7) min (range 84-166 min) respectively for the non-simultaneous (second VATS for the recurrence of contralateral side after first VATS) and simultaneous (bilateral VATS in one operation) procedures. There was no postoperative mortality. However, prolonged air leakage (>7 d) occurred in one patient (7.7%) who recovered after conservative treatment. The mean duration of chest tube drainage was 3.1 d and the median follow up period was 3.4 years. Conclusions: VATS is a safe and effective procedure in the treatment of bilateral PSP. Bilateral VATS is only recommended for patients with simultaneously bilateral PSP, because the incidence of recurrence, even with visible bullae, was not so high in my group and in some previous literature. Bilateral VATS in a supine position should only be used in selective cases, because of possible pleural adhesion or hidden bullae on the posterior side.  相似文献   
144.
The present study explores Greek parents’ views on parental educational involvement and its impact on adolescent scholastic and social development. Specifically, aspects of parental involvement such as the achieved objectives of current parent–school communication, the psychological climate dominating teacher–parent interactions and parents’ suggestions for improvement of current policies and practices are examined. Four hundred and seventy‐five parents participated in the study. Findings showed that family–school communication is believed to be insufficient in Greece, despite the fact that parents tend to: (1) regard their cooperation with teachers as determinative of adolescent academic and psychosocial development; (2) consider teachers to be friendly and caring; and (3) believe that secondary school provides some opportunities for constructive parental involvement. These paradoxes are discussed and explained as a result of radical changes in current social and educational values, principles and objectives.  相似文献   
145.
Thomas Uebel 《Metascience》2013,22(2):481-484
  相似文献   
146.
147.
This study provides a foundation for discussion of major issues facing community colleges in America. The purpose of the study was to ascertain how many community college presidents rank order issues facing their institutions, now and five years hence. Additionally, the study sought to more comprehensively examine recent literature about issues facing community colleges for purposes of comparison with the findings of the study, and for explication of issues identified. The data for analysis were collected from a population survey of all public and private community college presidents listed in the Education Directory of Colleges and Universities, 1981‐1982. Issues used in the survey were identified a priori, from a review of the literature, and were validated using a panel of community college presidents. The major findings were that both public and private community college presidents agree that the top issues facing their institutions five years hence are: financial support for institution, achieving institutional mission, and maintaining enrollments. Other major current issues include faculty and staff relations, planning and administering the budget, governing board relations, administrative team relations, state relations, public and community relations, and program development and evaluation. Additionally, questions were raised in the study regarding “presidential priority rankings of issues,” based upon directions suggested in the literature review about what issues seem most pressing in the decade of the 1980s.  相似文献   
148.
Tested was the effect of two persuasive messages presented by a credible communicator on the attitudes toward energy conservation of 180 preservice elementary teachers. The study asked the following questions: (1) Can attitudes toward energy conservation be positively changed with a brief, belief-laden communication? (2) Do positive attitude gains between pre- and post-tests, if any, dissipate within three weeks following the treatment? (3) Do the integrated and the nonintegrated communications affect energy attitudes of three subgroups (abstract, concrete differentiator and concrete thinkers) of the sample differently? The important finding was that both experimental treatments, integrated and nonintegrated, were equally effective and significantly more effective in attitude change than the control. Secondly, the finding that neither experimental treatment dissipated in effect, at least for three weeks, suggests some duration of brief treatment periods. And finally, the attitude changes are as likely to occur when concrete differentiators are presented with a nonintegrated as an integrated treatment, but abstract thinkers exposed to the integrated treatment and concrete thinkers exposed to the nonintegrated treatment sustain a changed attitude to a greater degree than other combinations of treatment and cognitive processing styles.  相似文献   
149.
This investigation identifies demographic, media, and social correlates of verbally aggressive communication in adolescence. Mail surveys were completed and returned by 2,300 adolescents between the ages of 13 and 15. These adolescents were asked about the prevalence of verbal and physical aggression, the context in which it occurred, demographics, and the interpersonal and media influences in their lives. The results indicate that verbal aggression is widespread, that committing and experiencing verbal aggression is largely reciprocal, that there is a strong relationship between committing verbal and physical aggression, and that peer social influence and listening to violently oriented music are mildly related to verbal aggression in adolescents. These findings suggest more resources should be allocated to teaching adolescents to understand and control verbal aggression. Further, they provide important answers to many prevention and intervention programmatic questions, including context, content, and targeting concerns. Since the negative consequences of verbal aggression are severe and long lasting, decreasing this destructive communication behavior should significantly improve the lives of many adolescents. These and other practical implications are expanded upon and discussed.  相似文献   
150.
The concepts of randomness and variation are pervasive in science. The purpose of this study was to document how post-secondary life science students explain randomness and variation, infer relationships between their explanations, and ability to describe and identify appropriate and inappropriate variation, and determine if students can identify sources of variation. An instrument designed to test statistical concepts was administered to 282 college students from three universities, ranging from introductory non-science majors to science graduate students. Students readily distinguished between causes of variation. A naïve no-pattern concept of randomness persisted from first-year non-science majors to senior-level science majors, contributing to incorrect responses on the variation instrument. Students’ expressions of randomness were better predictors of performance on the variation instrument than their expressions of variation. It is argued that inclusion of everyday language uses of randomness in instruction can bridge the gap between vernacular and scientific uses of this term.  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