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   15002篇
  免费   180篇
  国内免费   12篇
教育   10236篇
科学研究   1322篇
各国文化   158篇
体育   1522篇
综合类   22篇
文化理论   104篇
信息传播   1830篇
  2021年   109篇
  2020年   220篇
  2019年   311篇
  2018年   356篇
  2017年   439篇
  2016年   392篇
  2015年   247篇
  2014年   338篇
  2013年   2730篇
  2012年   289篇
  2011年   330篇
  2010年   266篇
  2009年   299篇
  2008年   279篇
  2007年   274篇
  2006年   261篇
  2005年   234篇
  2004年   475篇
  2003年   363篇
  2002年   392篇
  2001年   254篇
  2000年   262篇
  1999年   210篇
  1998年   109篇
  1997年   127篇
  1996年   157篇
  1995年   145篇
  1994年   134篇
  1993年   131篇
  1992年   184篇
  1991年   185篇
  1990年   165篇
  1989年   218篇
  1988年   177篇
  1987年   212篇
  1986年   181篇
  1985年   234篇
  1984年   191篇
  1983年   176篇
  1982年   156篇
  1981年   131篇
  1980年   112篇
  1979年   177篇
  1978年   137篇
  1977年   121篇
  1976年   140篇
  1975年   103篇
  1974年   120篇
  1973年   96篇
  1971年   107篇
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
991.
新世纪我国老年体育发展的困境与出路   总被引:1,自引:0,他引:1  
通过对新世纪我国老年体育发展所面临的主要困境与产生困境的社会背景进行分析和讨论,指出应加大政府宏观指导的力度、完善老年体育管理体制,注重老年体育消费市场的开发,加大老年体育专业指导人员的培养力度,拓宽筹集老年体育活动资金的渠道,丰富老年体育活动内容等。  相似文献   
992.
Librarianship has a long tradition of collaboration and cooperation between libraries, but the literature yields scant evidence of formal partnerships in practice in special libraries. This column explores the barriers to collaboration for special libraries, from organizational culture to legal constraints, as well as the potential benefits and how librarians can overcome the barriers to reap these benefits. Different types of collaboration, including among similar special libraries and between special libraries and other types of libraries and related organizations, as well as informal and formal cooperation, and short-term and long-term partnerships, are discussed. Collaboration and cooperation were part of the impetus to form professional associations. The column provides a brief history of professional library associations and their role in supporting library partnerships in the United States. The conclusion explores how the increasingly digital nature of information and library work affects collaborative library efforts and where the future of these efforts may lie, especially for special libraries.  相似文献   
993.
994.
从素质教育的要求出发,对高师、体育院校篮球专修课教学的现状进行了分析,提出了篮球专修课必须改变以竞技体育为指导思想、以技术教学为中心的模式,向以适应素质教育的教学指导思想转变,改革教学方式和方法、拓宽知识面,重视学生创造性、自学性能力的培养,加强师资队伍建设,健全评价体系的一系列观点和思考。  相似文献   
995.
Abstract

Predicated upon the premise that leisure needs are socially determined and therefore dynamic qualities of leisure motivation, this field study investigated the effects of outcome (winning, losing, no outcome) of leisure participation on male and female subjects' leisure needs. Subjects were 438 players of 60 teams in the intramural basketball program comprised of competitive and recreational leagues. Factor analysis produced seven need factors, of which three dealt with interpersonal relationships, two with competence and two with escape or diversion. ANOVAs performed on the resultant factor scores showed that successful and unsuccessful leisure experiences strongly shaped subjects' needs for leisure participation, but these effects were often mediated by the sex of subjects and the competitive levels of leagues in which they played. Generally, winning and losing had just the opposite effects on males' and females' needs; winning increased females' and decreased males' needs. The effects of competitiveness of league types suggested that competitive and recreational leagues serve different psychological functions for males and females because the two leagues are expected to fulfill different leisure needs.  相似文献   
996.
997.
998.
The U.S. government technical report is a primary means by which the results of federally funded research and development (R&D) are transferred to the U.S. aerospace industry. However, little is known about this information product in terms of its actual use, importance, and value in the transfer of federally funded R&D. Little is also known about the intermediary-based system that is used to transfer the results of federally funded R&D to the U.S. aerospace industry. To help establish a body of knowledge, the U.S. government technical report is being investigated as part of the NASA/DoD Aerospace Knowledge Diffusion Research Project. In this article, we summarize the literature on the U.S. government technical report and present the results of a survey of U.S. aerospace engineers and scientists that solicited their opinions concerning the format of NASA Langley Research Center (LaRC)-authored technical reports. To learn more about the preferences of U.S. aerospace engineers and scientists concerning the format of NASA LaRC-authored technical reports, we surveyed 133 report producers (i.e., authors) and 137 report users in March–April 1996. Questions covered such topics as: (a) the order in which report components are read; (b) components used to determine if a report would be read; (c) those components that could be deleted; (d) the placement of such components as the symbols list; (e) the desirability of a table of contents; (f) the format of reference citations; (g) column layout and right margin treatment; and (h) writing style in terms of person and voice. Mail (self-reported) surveys were used to collect the data. The response rates for report producers (i.e., authors) was 68% and for users, was 62%.  相似文献   
999.
Acetaminophen (APAP) a commonly used drug for decrease the fever and pain but is capable to induced hepatotoxicity at over dose. This study was carried out to investigate the effect of APAP on the expression of anti-apoptotic and antioxidative defense genes, and whether aldose reductase over-expressing plasmid capable to protect against APAP-induced oxidative stress and cell death. APAP treatment induced oxidative stress and hepatotoxicity, and significantly increased aldose reductase mRNA and protein expression in mouse hepatocyte (AML-12). Unexpectedly, AML-12 cells over-expressing aldose reductase augmented APAP-induced reduction in cell viability, reactive oxygen species (ROS) production, glutathione (GSH) depletion and glutathione S-transferase A2 expression. Moreover, over-expression of aldose reductase potentiated APAP induced reduction on proliferating cell nuclear antigen, B cell lymphoma-extra large (bcl-xL), catalase, glutathione peroxidase-1 (GPx-1) and abolished APAP-induced B-cell lymphoma 2 (bcl-2) inductions. Further, over-expression of aldose reductase significantly abolished AMP activated protein kinase (AMPK) activity in APAP-treated cells and induced p53 expression. This results demonstrate that APAP induced toxicity in AML-12, increased aldose reductase expression, and over-expression of aldose reductase render this cell more susceptible to APAP induced oxidative stress and cell death, this probably due to inhibition AMPK or bcl-2 activity, or may due to competition between aldose reductase and glutathione reductase for NADPH.  相似文献   
1000.
The present study explored the environmental and genetic etiologies of the longitudinal relations between prereading skills and reading and spelling. Twin pairs (n = 489) were assessed before kindergarten (M = 4.9 years), post‐first grade (M = 7.4 years), and post‐fourth grade (M = 10.4 years). Genetic influences on five prereading skills (print knowledge, rapid naming, phonological awareness, vocabulary, and verbal memory) were primarily responsible for relations with word reading and spelling. However, relations with post‐fourth‐grade reading comprehension were due to both genetic and shared environmental influences. Genetic and shared environmental influences that were common among the prereading variables covaried with reading and spelling, as did genetic influences unique to verbal memory (only post‐fourth‐grade comprehension), print knowledge, and rapid naming.  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