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   16324篇
  免费   247篇
  国内免费   52篇
教育   11973篇
科学研究   1195篇
各国文化   174篇
体育   1203篇
综合类   44篇
文化理论   78篇
信息传播   1956篇
  2022年   89篇
  2021年   178篇
  2020年   231篇
  2019年   357篇
  2018年   502篇
  2017年   544篇
  2016年   497篇
  2015年   323篇
  2014年   449篇
  2013年   3381篇
  2012年   451篇
  2011年   465篇
  2010年   409篇
  2009年   392篇
  2008年   412篇
  2007年   386篇
  2006年   412篇
  2005年   362篇
  2004年   249篇
  2003年   245篇
  2002年   228篇
  2001年   365篇
  2000年   289篇
  1999年   248篇
  1998年   157篇
  1997年   144篇
  1996年   146篇
  1995年   129篇
  1994年   141篇
  1993年   120篇
  1992年   202篇
  1991年   189篇
  1990年   230篇
  1989年   201篇
  1988年   162篇
  1987年   168篇
  1986年   172篇
  1985年   163篇
  1984年   165篇
  1983年   146篇
  1982年   112篇
  1981年   123篇
  1980年   116篇
  1979年   171篇
  1978年   142篇
  1977年   97篇
  1976年   109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 656 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.
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   
3.
4.
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   
5.
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   
6.
7.
8.
9.
10.
Gordon  R. S.  Franklin  K. L.  Baker  J.  Davies  B. 《Sports Engineering》2004,7(3):131-138
Sports Engineering - A Monark cycle ergometer is a device globally used in physiological studies to measure the work and energy levels of exercising humans. In this paper a rope-braked cycle...  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