全文获取类型
收费全文 | 20711篇 |
免费 | 307篇 |
国内免费 | 58篇 |
专业分类
教育 | 15245篇 |
科学研究 | 1433篇 |
各国文化 | 247篇 |
体育 | 1584篇 |
综合类 | 45篇 |
文化理论 | 118篇 |
信息传播 | 2404篇 |
出版年
2021年 | 224篇 |
2020年 | 301篇 |
2019年 | 472篇 |
2018年 | 643篇 |
2017年 | 696篇 |
2016年 | 643篇 |
2015年 | 413篇 |
2014年 | 586篇 |
2013年 | 4289篇 |
2012年 | 559篇 |
2011年 | 559篇 |
2010年 | 491篇 |
2009年 | 498篇 |
2008年 | 531篇 |
2007年 | 495篇 |
2006年 | 513篇 |
2005年 | 451篇 |
2004年 | 343篇 |
2003年 | 324篇 |
2002年 | 304篇 |
2001年 | 419篇 |
2000年 | 354篇 |
1999年 | 313篇 |
1998年 | 198篇 |
1997年 | 196篇 |
1996年 | 226篇 |
1995年 | 193篇 |
1994年 | 203篇 |
1993年 | 168篇 |
1992年 | 267篇 |
1991年 | 241篇 |
1990年 | 280篇 |
1989年 | 249篇 |
1988年 | 204篇 |
1987年 | 206篇 |
1986年 | 213篇 |
1985年 | 200篇 |
1984年 | 206篇 |
1983年 | 186篇 |
1982年 | 163篇 |
1981年 | 168篇 |
1980年 | 158篇 |
1979年 | 204篇 |
1978年 | 184篇 |
1977年 | 125篇 |
1976年 | 139篇 |
1975年 | 124篇 |
1974年 | 121篇 |
1973年 | 117篇 |
1971年 | 126篇 |
排序方式: 共有10000条查询结果,搜索用时 31 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.
Research in Higher Education - Increasingly, undergraduates take more than 4 years to complete a baccalaureate, a situation widely perceived as a waste of time and money, for students,... 相似文献
3.
David Sánchez-Oliva Rebecca M. Leech Alberto Grao-Cruces Irene Esteban-Cornejo Carmen Padilla-Moledo Oscar L. Veiga 《Journal of sports sciences》2020,38(9):1062-1069
ABSTRACTThe 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.
In the IR field it is clear that the value of a system depends on the cost and benefit profiles of its users. It would seem obvious that different users would prefer different systems. In the TREC-9 filtering track, systems are evaluated by a utility measure specifying a given cost and benefit. However, in the study of decision systems it is known that, in some cases, one system may be unconditionally better than another. In this paper we employ a decision theoretic approach to find conditions under which an Information Filtering (IF) system is unconditionally superior to another for all users regardless of their cost and benefit profiles.It is well known that if two IF systems have equal precision the system with better recall will be preferred by all users. Similarly, with equal recall, better precision is universally preferred. We confirm these known results and discover an unexpected dominance relation in which a system with lower recall will be universally preferred provided its precision is sufficiently higher. 相似文献
7.
8.
Paul Morris 《比较教育学》1996,32(1):95-110
The economic success of some of the countries within the East Asian region has generated a range of studies which have attempted to identify the sources of that growth. One strand within these analyses has focused on the critical role of schooling in the accumulation of human capital. This paper examines the role which education has played in the rapid development of the four 'Asian Tigers'; namely: Hong Kong, Taiwan, South Korea and Singapore. It is argued that whilst patterns of educational provision displayed some common features there were also significant differences in other areas such as the role of the state, sources of educational funding, the role of technical education and of the school curriculum. 相似文献
9.
10.
Our argument in this paper is that the model of literary progression which Bakhtin (1981, 1986) expounds in his writing on the chronotope can generate insight into the processes through which pupils improve their writing. We suggest more generally that there are concepts and clues in Bakhtin's historical model of the development of the European novel and in his theory of dialogue which can be helpful in both the evaluation and teaching of classroom writing. 相似文献