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   8467篇
  免费   145篇
  国内免费   323篇
教育   3417篇
科学研究   1289篇
各国文化   9篇
体育   2208篇
综合类   1012篇
文化理论   25篇
信息传播   975篇
  2024年   2篇
  2023年   21篇
  2022年   92篇
  2021年   198篇
  2020年   275篇
  2019年   213篇
  2018年   183篇
  2017年   191篇
  2016年   164篇
  2015年   253篇
  2014年   491篇
  2013年   806篇
  2012年   675篇
  2011年   684篇
  2010年   479篇
  2009年   517篇
  2008年   629篇
  2007年   645篇
  2006年   502篇
  2005年   442篇
  2004年   341篇
  2003年   298篇
  2002年   228篇
  2001年   148篇
  2000年   85篇
  1999年   92篇
  1998年   67篇
  1997年   68篇
  1996年   46篇
  1995年   26篇
  1994年   28篇
  1993年   12篇
  1992年   12篇
  1990年   6篇
  1989年   2篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1979年   1篇
  1978年   4篇
  1977年   1篇
  1976年   1篇
  1957年   1篇
排序方式: 共有8935条查询结果,搜索用时 203 毫秒
101.
科技信息的开放获取已成为影响学术信息交流与科学发展的重大问题,深刻地影响到科技政策、科技支撑环境发展战略和科技信息服务模式。一大批科学家、科研机构和许多国家的科学管理与科研资助机构,都积极地推动科技信息的开放获取。他们或者制定开放获取政策、要求或鼓励科研人员提供科研成果的开放获取,或者支持开放出版期刊,或者建立机构开放存储库、支持本机构科研成果开放获取。通过这一系列的措施,科学界希望能够促进科研成果不受限制地广泛传播和自由获取、以及促进科研成果通过公共机制长期可靠保存和利用,以保障科技知识资产的国家保护和科研机构的知识资产管理。  相似文献   
102.
在1952—1970年担任西储大学图书馆学院院长期间,谢拉积极探索文献工作教育:在学科理论方面,进行文献工作学科理论建设;在学术研究方面,设立美国图书馆学院第一个专门的文献工作研究中心“文献工作与交流研究中心”;在教学活动方面,在图书馆学教育项目中引入文献工作相关课程,强化以文献工作为重点的专业图书馆人才培养。谢拉的文献工作教育是对传统图书馆学教育的改造,适应了图书馆学教育专门化的发展趋势,其立足点是以文献工作提升图书馆职业的社会价值,服务于图书馆人才培养,体现出明显的图书馆本位立场。谢拉领导下的西储大学图书馆学院的文献工作教育是一种过渡形态的早期情报学教育,促进了20世纪美国图书馆学教育向图书情报学教育格局的转型。参考文献62。  相似文献   
103.
Many studies demonstrate differences in the coverage of citing publications in Google Scholar (GS) and Web of Science (WoS). Here, we examine to what extent citation data from the two databases reflect the scholarly impact of women and men differently. Our conjecture is that WoS carries an indirect gender bias in its selection criteria for citation sources that GS avoids due to criteria that are more inclusive. Using a sample of 1250 U.S. researchers in Sociology, Political Science, Economics, Cardiology and Chemistry, we examine gender differences in the average citation coverage of the two databases. We also calculate database-specific h-indices for all authors in the sample. In repeated simulations of hiring scenarios, we use these indices to examine whether women's appointment rates increase if hiring decisions rely on data from GS in lieu of WoS. We find no systematic gender differences in the citation coverage of the two databases. Further, our results indicate marginal to non-existing effects of database selection on women's success-rates in the simulations. In line with the existing literature, we find the citation coverage in WoS to be largest in Cardiology and Chemistry and smallest in Political Science and Sociology. The concordance between author-based h-indices measured by GS and WoS is largest for Chemistry followed by Cardiology, Political Science, Sociology and Economics.  相似文献   
104.
This study explores science communication on Twitter by investigating a sample of tweets referring to academic papers in five different scientific fields. The specifications of science communicators on Twitter, the characteristics of those who initiate actions (by tweeting), the extent and quality of reactions (retweeting), individual and group interactions, and the distribution of tweets across types of engagement in the process of science communication (i.e., dissemination, consultation, and evaluation) were explored. A broad array of actors is involved in the communication of science on Twitter, with individual citizens and individual researchers playing an important role. In principle, this is promising for creating direct interaction, which can be difficult through more traditional mass media. The vast majority of communication activities regarding academic papers is undigested dissemination with almost no sign of debate, contestation, or collective reflection. Another general finding of this study is that bot accounts play a major role in the science communication landscape on Twitter.  相似文献   
105.
Citation averages, and Impact Factors (IFs) in particular, are sensitive to sample size. Here, we apply the Central Limit Theorem to IFs to understand their scale-dependent behavior. For a journal of n randomly selected papers from a population of all papers, we expect from the Theorem that its IF fluctuates around the population average μ, and spans a range of values proportional to σ/n, where σ2 is the variance of the population's citation distribution. The 1/n dependence has profound implications for IF rankings: The larger a journal, the narrower the range around μ where its IF lies. IF rankings therefore allocate an unfair advantage to smaller journals in the high IF ranks, and to larger journals in the low IF ranks. As a result, we expect a scale-dependent stratification of journals in IF rankings, whereby small journals occupy the top, middle, and bottom ranks; mid-sized journals occupy the middle ranks; and very large journals have IFs that asymptotically approach μ. We obtain qualitative and quantitative confirmation of these predictions by analyzing (i) the complete set of 166,498 IF & journal-size data pairs in the 1997–2016 Journal Citation Reports of Clarivate Analytics, (ii) the top-cited portion of 276,000 physics papers published in 2014–2015, and (iii) the citation distributions of an arbitrarily sampled list of physics journals. We conclude that the Central Limit Theorem is a good predictor of the IF range of actual journals, while sustained deviations from its predictions are a mark of true, non-random, citation impact. IF rankings are thus misleading unless one compares like-sized journals or adjusts for these effects. We propose the Φ index, a rescaled IF that accounts for size effects, and which can be readily generalized to account also for different citation practices across research fields. Our methodology applies to other citation averages that are used to compare research fields, university departments or countries in various types of rankings.  相似文献   
106.
Dimensions is a partly free scholarly database launched by Digital Science in January 2018. Dimensions includes journal articles and citation counts, making it a potential new source of impact data. This article explores the value of Dimensions from an impact assessment perspective with an examination of Food Science research 2008–2018 and a random sample of 10,000 Scopus articles from 2012. The results include high correlations between citation counts from Scopus and Dimensions (0.96 by narrow field in 2012) as well as similar average counts. Almost all Scopus articles with DOIs were found in Dimensions (97% in 2012). Thus, the scholarly database component of Dimensions seems to be a plausible alternative to Scopus and the Web of Science for general citation analyses and for citation data in support of some types of research evaluations.  相似文献   
107.
新时期我国社会主要矛盾已经转化为人民日益增长的美好生活需要和不平衡不充分的发展之间的矛盾,这将对体育产业发展提出更高的要求。现阶段,河南省体育产业现状还不能满足人民日益增长的健身需要。因此,我们应理清现阶段体育产业发展的主要矛盾并积极探索体育产业创新发展的路径,为缓解新时期社会主要矛盾而贡献体育智慧。 采用文献资料法、专家咨询法、实地调查法、逻辑推理等研究方法,深入探析现阶段河南省体育产业发展现状与人民日益增长的健身需要还存在的矛盾,并在充分认识河南省体育产业发展优势、理清体育产业发展的矛盾基础上,提出中原特色体育产业创新发展路径:积极推进中原特色“体育+旅游”融合发展模式,满足人民群众体育旅游需求;大力发展中原特色户外健身休闲产业,满足人民群众的休闲健身需求;以中原特色体育竞赛活动带动体育产业发展,满足群众观赏赛事需求;积极建设中原特色传统体育文化传承核心区,带动传统体育文化产业发展,满足人民群众的体育文化精神需求;合理开发公共体育服务场地资源,满足人民群众健身场地需求;积极培育社会性组织管理体系,缓解政府体育组织管理体系管理职能压力。  相似文献   
108.
针对文献学课程作为选修课常常受到文献检索等课程的挤压,作为必修课又受到教学对象主、客观两方面因素的制约的情况,提出文献学对于文史哲等专业的治学研究有指导作用,对于学生知识体系的建构和完善有着非同一般的意义,应该成为文科专业的基础课。改进文献学的教学现状,教师必须注意文献学观念的转变,注意与国学教育相融合,提升自己的学术含量,提高自己的文化品格,实现教学策略的调整。  相似文献   
109.
The promotion of students’ achievement and competence in the so-called STEM disciplines is one cornerstone of current educational research and practice. In particular, as early as elementary school, the fostering of an adequate understanding of science is a normative goal of science education. It facilitates students’ science learning and enables them to understand the nature and development of scientific knowledge. Based on the relevance of the promotion of young children’s understanding of science, a corresponding science intervention was recently developed and successfully evaluated in a first study under highly controlled conditions. The goal of the present study was to investigate the effectiveness of this intervention when implemented in practice. One hundred seventeen third- and fourth-grade students and 10 trained course instructors participated in this study. We applied a randomized block design with waitlist control groups and repeated measures. The results revealed that children assigned to the intervention compared with children assigned to the waitlist control group showed better inquiry-related methodological competencies (a better understanding of the scientific inquiry cycle and experimentation strategies) and a higher need for cognition. The findings point to the successful implementation of the intervention and are compared with the results of the first study.  相似文献   
110.
ABSTRACT

The objective of this study was to analyse the effect of the use of social networks in smartphones or playing video games on the passing decision-making performance in professional soccer athletes. Participants were 25 male professional soccer athletes (mean ± SD: age 23.4 ± 2.8 years). The participants performed three randomised conditions divided into three groups: control (CON), smartphone (SMA), and video game (VID). Before and after each experimental condition, the Stroop Task assessed the level of induced mental fatigue. Then, the athletes performed a simulated soccer match. A CANON® camera recorded the matches for further analysis on passing decision-making performance. A group effect was identified (< .01) with impairment on passing decision-making performance for the SMA (p = .01, ES = 0.5) and VID (p = .01, ES = 0.5) conditions. We concluded that the use of social networks on smartphones and/or playing video games right before official soccer matches might impair the passing decision-making performance in professional soccer athletes.  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