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   18665篇
  免费   286篇
  国内免费   55篇
教育   13765篇
科学研究   1288篇
各国文化   207篇
体育   1391篇
综合类   44篇
文化理论   104篇
信息传播   2207篇
  2022年   102篇
  2021年   202篇
  2020年   270篇
  2019年   430篇
  2018年   577篇
  2017年   624篇
  2016年   572篇
  2015年   380篇
  2014年   530篇
  2013年   3921篇
  2012年   500篇
  2011年   522篇
  2010年   457篇
  2009年   458篇
  2008年   488篇
  2007年   449篇
  2006年   465篇
  2005年   409篇
  2004年   295篇
  2003年   296篇
  2002年   275篇
  2001年   413篇
  2000年   342篇
  1999年   295篇
  1998年   184篇
  1997年   175篇
  1996年   191篇
  1995年   164篇
  1994年   167篇
  1993年   166篇
  1992年   240篇
  1991年   216篇
  1990年   251篇
  1989年   216篇
  1988年   178篇
  1987年   188篇
  1986年   188篇
  1985年   188篇
  1984年   174篇
  1983年   157篇
  1982年   126篇
  1981年   139篇
  1980年   126篇
  1979年   182篇
  1978年   158篇
  1977年   104篇
  1976年   121篇
  1975年   111篇
  1973年   101篇
  1971年   103篇
排序方式: 共有10000条查询结果,搜索用时 17 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.
It is generally acknowledged that expatriate British players and coaches were instrumental in soccer’s radiant global diffusion and that different technical and tactical emphases developed according to particular geographical locations and cultural milieu. As the twentieth century unfolded, the trend reversed with increased inward flows of elite foreign playing and coaching labour challenging the distinctive and erstwhile dominant occupational culture of the English game. This paper explores the dynamics and tensions of subcultural modification and adaptation at the British: migrant coaching talent interface. Owing to issues associated with access, the occupational subculture of elite-level football is impenetrable to most researchers. Previous employment in professional soccer allowed this author to overcome such impediments, permitting access to a range of high-status national and international players and coaches (n = 25) affecting and affected by occupational subcultural change. This enabled a distinctive research platform combining insider knowledge and grounded experience with academic orthodoxy. The paper is built upon primary data collected in semi-structured interviews and critical analysis of emerging themes. In doing so, it offers a fresh dimension to understanding the impact of globalization on elite professional English soccer. Key findings indicated the opinion of British coaches on the impact of this foreign influx polarized. Although many demonstrated an enlightened standpoint, adopting innovative practices introduced by overseas coaching talent, these views were counter-balanced by evidence of a myopic arrogance bordering on xenophobic resistance to change in what now has to be considered the global rather than the ‘English’ game.  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.
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.
This study investigated the validity and reliability of the GymAware PowerTool (GPT). Thirteen resistance trained participants completed three visits, consisting of three repetitions of free-weight back squat, bench press, deadlift (80% one repetition maximum), and countermovement jump. Bar displacement, peak and mean velocity, peak and mean force, and jump height were calculated using the GPT, a three-dimensional motion capture system (Motion Analysis Corporation; 150 Hz), and a force plate (Kistler; 1500 Hz). Least products regression were used to compare agreeability between devices. A within-trial one-way ANOVA, typical error (TE; %), and smallest worthwhile change (SWC) were used to assess reliability. Regression analysis resulted in R2 values of >0.85 for all variables excluding deadlift mean velocity (R2 = 0.54–0.69). Significant differences were observed between visits 3-2 for bench press bar displacement (0.395 ± 0.055 m; 0.383 ± 0.053 m), and deadlift bar displacement (0.557 ± 0.034 m; 0.568 ± 0.034 m). No other significant differences were found. Low to moderate TE (0.6–8.8%) were found for all variables, with SWC ranging 1.7–7.4%. The data provides evidence that the GPT can be used to measure kinetic and kinematic outputs, however, care should be taken when monitoring deadlift performance.  相似文献   
7.
Abstract

This paper provides a methodology to study the characteristics of the research output from a university department. The faculty publications and their cited references over a 10-year period were used as the basis for this study to identify their publishing patterns and the types of material they are publishing; a core set of journals and other resources they are publishing in and citing over this period; the characteristics of the journals in which they publish and cite; the degree of openness of their publications and their citation advantage; and the age of resources that are referenced.  相似文献   
8.
Measuring Search Engine Quality   总被引:12,自引:3,他引:9  
The effectiveness of twenty public search engines is evaluated using TREC-inspired methods and a set of 54 queries taken from real Web search logs. The World Wide Web is taken as the test collection and a combination of crawler and text retrieval system is evaluated. The engines are compared on a range of measures derivable from binary relevance judgments of the first seven live results returned. Statistical testing reveals a significant difference between engines and high intercorrelations between measures. Surprisingly, given the dynamic nature of the Web and the time elapsed, there is also a high correlation between results of this study and a previous study by Gordon and Pathak. For nearly all engines, there is a gradual decline in precision at increasing cutoff after some initial fluctuation. Performance of the engines as a group is found to be inferior to the group of participants in the TREC-8 Large Web task, although the best engines approach the median of those systems. Shortcomings of current Web search evaluation methodology are identified and recommendations are made for future improvements. In particular, the present study and its predecessors deal with queries which are assumed to derive from a need to find a selection of documents relevant to a topic. By contrast, real Web search reflects a range of other information need types which require different judging and different measures.  相似文献   
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