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   28738篇
  免费   271篇
  国内免费   56篇
教育   21502篇
科学研究   2452篇
各国文化   183篇
体育   1558篇
综合类   45篇
文化理论   465篇
信息传播   2860篇
  2021年   188篇
  2020年   242篇
  2019年   388篇
  2018年   2669篇
  2017年   2641篇
  2016年   2093篇
  2015年   474篇
  2014年   591篇
  2013年   3564篇
  2012年   689篇
  2011年   1235篇
  2010年   1285篇
  2009年   847篇
  2008年   1082篇
  2007年   1594篇
  2006年   490篇
  2005年   766篇
  2004年   732篇
  2003年   644篇
  2002年   379篇
  2001年   385篇
  2000年   333篇
  1999年   270篇
  1998年   173篇
  1997年   182篇
  1996年   183篇
  1995年   151篇
  1994年   168篇
  1993年   128篇
  1992年   217篇
  1991年   204篇
  1990年   237篇
  1989年   214篇
  1988年   171篇
  1987年   177篇
  1986年   177篇
  1985年   172篇
  1984年   175篇
  1983年   151篇
  1982年   117篇
  1981年   131篇
  1980年   117篇
  1979年   173篇
  1978年   146篇
  1977年   99篇
  1976年   111篇
  1975年   102篇
  1974年   91篇
  1973年   97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.
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.
David Kaldewey 《Minerva》2018,56(2):161-182
This article analyzes the concept of “grand challenges” as part of a shift in how scientists and policymakers frame and communicate their respective agendas. The history of the grand challenges discourse helps to understand how identity work in science and science policy has been transformed in recent decades. Furthermore, the question is raised whether this discourse is only an indicator, or also a factor in this transformation. Building on conceptual history and historical semantics, the two parts of the article reconstruct two discursive shifts. First, the observation that in scientific communication references to “problems” are increasingly substituted by references to “challenges” indicates a broader cultural trend of how attitudes towards what is problematic have shifted in the last decades. Second, as the grand challenges discourse is rooted in the sphere of sports and competition, it introduces a specific new set of societal values and practices into the spheres of science and technology. The article concludes that this process can be characterized as the sportification of science, which contributes to self-mobilization and, ultimately, to self-optimization of the participating scientists, engineers, and policymakers.  相似文献   
5.
6.
Letters     
  相似文献   
7.
Editorial     
B. Sury 《Resonance》2018,23(7):723-725
  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