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   17447篇
  免费   283篇
  国内免费   72篇
教育   12669篇
科学研究   1343篇
各国文化   196篇
体育   1318篇
综合类   79篇
文化理论   94篇
信息传播   2103篇
  2022年   101篇
  2021年   226篇
  2020年   271篇
  2019年   409篇
  2018年   543篇
  2017年   600篇
  2016年   535篇
  2015年   383篇
  2014年   522篇
  2013年   3459篇
  2012年   518篇
  2011年   532篇
  2010年   485篇
  2009年   449篇
  2008年   479篇
  2007年   479篇
  2006年   484篇
  2005年   400篇
  2004年   285篇
  2003年   280篇
  2002年   256篇
  2001年   395篇
  2000年   311篇
  1999年   262篇
  1998年   166篇
  1997年   148篇
  1996年   147篇
  1995年   132篇
  1994年   142篇
  1993年   124篇
  1992年   201篇
  1991年   190篇
  1990年   230篇
  1989年   200篇
  1988年   160篇
  1987年   168篇
  1986年   171篇
  1985年   165篇
  1984年   162篇
  1983年   147篇
  1982年   112篇
  1981年   123篇
  1980年   115篇
  1979年   170篇
  1978年   142篇
  1977年   100篇
  1976年   108篇
  1975年   101篇
  1973年   98篇
  1971年   101篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Early childhood is a sensitive period for learning and social skill development. The maturation of cerebral regions underlying social processing lays the foundation for later social-emotional competence. This study explored myelin changes in social brain regions and their association with changes in parent-rated social-emotional development in a cohort of 129 children (64 females, 0–36 months, 77 White). Results reveal a steep increase in myelination throughout the social brain in the first 3 years of life that is significantly associated with social-emotional development scores. These findings add knowledge to the emerging picture of social brain development by describing neural underpinnings of human social behavior. They can contribute to identifying age-/stage-appropriate early life factors in this developmental domain.  相似文献   
2.
Fernandez  Frank  Baker  David P.  Fu  Yuan-Chih  Muñoz  Ismael G.  Ford  Karly Sarita 《Minerva》2021,59(1):79-98
Minerva - Over the course of the 20th century, unprecedented growth in scientific discovery was fueled by broad growth in the number of university-based scientists. During this period the American...  相似文献   
3.
ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.  相似文献   
4.
5.
6.
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   
7.
1.开发平台的选择 开发平台的选择有多种开发工具的组合(操作系统+网络数据库编程软件+脚本开发工具)支持网络教育平台的模块化开发.其中以Apache+MySQL+PHP技术颇具代表性.  相似文献   
8.
9.
10.
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