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   32015篇
  免费   577篇
  国内免费   553篇
教育   19800篇
科学研究   5497篇
各国文化   216篇
体育   2344篇
综合类   816篇
文化理论   185篇
信息传播   4287篇
  2022年   245篇
  2021年   565篇
  2020年   545篇
  2019年   502篇
  2018年   632篇
  2017年   634篇
  2016年   637篇
  2015年   783篇
  2014年   1122篇
  2013年   3849篇
  2012年   1485篇
  2011年   1673篇
  2010年   1521篇
  2009年   1393篇
  2008年   1422篇
  2007年   1564篇
  2006年   1538篇
  2005年   1347篇
  2004年   806篇
  2003年   758篇
  2002年   750篇
  2001年   719篇
  2000年   527篇
  1999年   532篇
  1998年   342篇
  1997年   289篇
  1996年   294篇
  1995年   266篇
  1994年   201篇
  1993年   206篇
  1992年   277篇
  1991年   257篇
  1990年   259篇
  1989年   281篇
  1988年   229篇
  1987年   220篇
  1986年   221篇
  1985年   234篇
  1984年   204篇
  1983年   209篇
  1982年   166篇
  1981年   152篇
  1980年   134篇
  1979年   232篇
  1978年   174篇
  1977年   169篇
  1976年   131篇
  1975年   125篇
  1974年   141篇
  1973年   121篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Working memory training improves children's cognitive performance on untrained tasks; however, little is known about the underlying neural mechanisms. This was investigated in 32 typically developing children aged 10–14 years (19 girls and 13 boys) using a randomized controlled design and multi-modal magnetic resonance imaging (Devon, UK; 2015–2016). Training improved working memory performance and increased intrinsic functional connectivity between the bilateral intraparietal sulci. Furthermore, improvements in working memory were associated with greater recruitment of the left middle frontal gyrus on a complex span task. Repeated engagement of fronto-parietal regions during training may increase their activity and functional connectivity over time, affording greater working memory performance. The plausibility of generalizable cognitive benefits from a neurobiological perspective and implications for neurodevelopmental theory are discussed.  相似文献   
2.
[目的/意义] 探索构建文献情报大数据知识资源体系,支撑面向多领域的智慧知识服务。[方法/过程] 基于AI应用需求,借鉴业界经验,梳理现有资源体系的问题,从多层次多维度扩展资源体系;构建可靠数据处理流程和计算平台,支持高效数据采集和处理;研发智能化数据治理工具,实现知识资源的有效治理,确保提供高质量数据资源。[结果/结论] 已初步形成覆盖多类型、多学科的科技文献大数据知识资源体系,构建完成高度自动化的数据采集治理流程,实施多重数据质量控制,积累数亿高质量数据,且为多个知识服务提供数据支撑。  相似文献   
3.
Genetic variation in the angiotensin II type 1 receptor (AT1R) has an important effect on the outcome of acute coronary syndrome (ACS) initiated treatment with captopril. This study aims to investigate the impact of genetic polymorphism of AT1R (rs5186 and rs275651) on the ACS outcome in Iraqi patients treated with captopril. A total of 250 Iraqi individuals with ACS were included in this case—control study and they were divided into two study groups; Study group 1 included 125 participants who were prescribed captopril, 25 mg twice daily and study group 2 included 125 participants who received no captopril as part of their ACS treatment (control study). The AT1R gene (rs5186) CC genotype was found to be associated with ST-elevation myocardial infarction (STEMI) (Odd’s ratio (O.R) = 1.2, P = 0.7), while AC was associated with Non-ST-elevation myocardial infarction (NSTEMI) and unstable angina (UA) (O.R = 1.2, P = 0.8). AC genotype is more prone to have Percutaneous coronary intervention (PCI) after ACS attack (O.R = 1.2, P = 0.6). CC genotype had a risk to get less improvement (O.R = 1.6, P = 0.5), so might require higher doses of captopril during acute coronary insult. The AT1R gene (rs275651) AA genotype was associated with UA (O.R = 1.3, P = 0.9). AA and AT genotypes were more prone to have PCI after ACS attack (O.R = 3.9 P = 0.2, O.R = 3.5, P = 0.3 respectively) and thus requiring higher doses of captopril. We conclude that the AT1R rs5186, rs275651 genetic polymorphisms might partially affect the clinical outcome of ACS patients treated with captopril and might have captopril resistance which requires higher doses.  相似文献   
4.
吴汉华  倪弘 《图书情报工作》2019,63(13):114-121
[目的/意义]欧洲阅读联盟是欧洲社会力量开展阅读活动的母平台,联盟成员所开展的阅读活动既有差异,也有共性,社会影响力大。通过对欧洲阅读联盟成员所办阅读活动及其规律的分析,可为我国公共图书馆主导与开展阅读活动提供借鉴。[方法/过程]概述欧洲阅读联盟,对其成员类型进行解析,并对每一成员的阅读项目进行共性分析,凝练出阅读活动的经验及规律。[结果/结论]我国应建立多级阅读推广力量,建立政府购买阅读服务长效机制,开放图书馆的阅读活动空间,提升阅读活动频率,开发多样化、差异化的阅读活动。  相似文献   
5.
In this digital ITEMS module, Dr. Jeffrey Harring and Ms. Tessa Johnson introduce the linear mixed effects (LME) model as a flexible general framework for simultaneously modeling continuous repeated measures data with a scientifically defensible function that adequately summarizes both individual change as well as the average response. The module begins with a nontechnical overview of longitudinal data analyses drawing distinctions with cross-sectional analyses in terms of research questions to be addressed. Nuances of longitudinal designs, timing of measurements, and the real possibility of missing data are then discussed. The three interconnected components of the LME model—(1) a model for individual and mean response profiles, (2) a model to characterize the covariation among the time-specific residuals, and (3) a set of models that summarize the extent that individual coefficients vary—are discussed in the context of the set of activities comprising an analysis. Finally, they demonstrate how to estimate the linear mixed effects model within an open-source environment (R). The digital module contains sample R code, diagnostic quiz questions, hands-on activities in R, curated resources, and a glossary.  相似文献   
6.
ABSTRACT

This forum brings together food, (in)security, and communication. The authors participating in this forum center communication as both process and tool for understanding, mitigating, and making meaning of food (in)security. The nine authors together discuss the role of communication in food (in)security, the central challenges for scholars and practitioners working on food (in)security, and the creative possibilities and impacts influencing the future of food (in)security. The forum produces a call for applied scholars to re-imagine communication frameworks in order to make meaningful differences in their communities.  相似文献   
7.
8.
高尔夫化是现代社会发展进程中一种特殊的化现象。通过对高尔夫化的历史演变和社会发展特征的分析,为进一步发展和完善我国高尔夫运动的理论研究,探讨高尔夫产业市场发展的基本规律,奠定理论研究基础。  相似文献   
9.
运用学习策略理论 ,并结合运动技能学习的特点 ,在田径技术教学中对运动系 2 0 0 1级学生进行了教学实验 ,初步得出以下结论 :在学习运动技能过程中施加学习策略训练有助于学生掌握运动技术 ;在培养学生运用学习策略的能力方面 ,语言法、调控法、认知体验三项指标得到明显改善 ,学习策略能力的培养是一个长期的过程。  相似文献   
10.
依托油脂行业 办好《中国油脂》   总被引:3,自引:1,他引:2  
介绍《中国油脂》依托油脂行业,办好期刊的做法和体会。  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