全文获取类型
收费全文 | 25980篇 |
免费 | 330篇 |
国内免费 | 63篇 |
专业分类
教育 | 18569篇 |
科学研究 | 2423篇 |
各国文化 | 293篇 |
体育 | 1777篇 |
综合类 | 49篇 |
文化理论 | 170篇 |
信息传播 | 3092篇 |
出版年
2021年 | 230篇 |
2020年 | 315篇 |
2019年 | 483篇 |
2018年 | 647篇 |
2017年 | 724篇 |
2016年 | 643篇 |
2015年 | 428篇 |
2014年 | 620篇 |
2013年 | 5202篇 |
2012年 | 589篇 |
2011年 | 616篇 |
2010年 | 532篇 |
2009年 | 531篇 |
2008年 | 568篇 |
2007年 | 543篇 |
2006年 | 565篇 |
2005年 | 495篇 |
2004年 | 373篇 |
2003年 | 358篇 |
2002年 | 327篇 |
2001年 | 475篇 |
2000年 | 415篇 |
1999年 | 363篇 |
1998年 | 233篇 |
1997年 | 228篇 |
1996年 | 254篇 |
1995年 | 212篇 |
1994年 | 241篇 |
1993年 | 238篇 |
1992年 | 346篇 |
1991年 | 345篇 |
1990年 | 364篇 |
1989年 | 351篇 |
1988年 | 292篇 |
1987年 | 309篇 |
1986年 | 317篇 |
1985年 | 318篇 |
1984年 | 321篇 |
1983年 | 306篇 |
1982年 | 249篇 |
1981年 | 255篇 |
1980年 | 233篇 |
1979年 | 332篇 |
1978年 | 303篇 |
1977年 | 207篇 |
1976年 | 224篇 |
1975年 | 204篇 |
1974年 | 177篇 |
1973年 | 198篇 |
1971年 | 184篇 |
排序方式: 共有10000条查询结果,搜索用时 62 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.
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
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.
Children are sensitive to a number of considerations influencing distributions of resources, including equality, equity, and reciprocity. We tested whether children use a specific type of reciprocity norm—market norms—in which resources are distributed differentially based strictly on amount offered in return. In two studies, 195 children 5–10 years and 60 adults distributed stickers to friends offering same or different amounts of money. Overall, participants distributed more equally when offers were the same and more unequally when offers were different. Although sensitive to why friends offered different amounts of money, children increasingly incorporated market norms into their distributions with age, as the oldest children and adults distributed more to those offering more, irrespective of the reasons provided. 相似文献
6.
As a group, students with learning disabilities (LD) have social difficulties. One possible explanation for these difficulties is the unique way they process social information. Although students with LD may differ from their nondisabled peers in their social cognition, investigators have suggested the presence of subgroups within the population of students with LD who may differ in their social competence and, thereby, shed light on the source of the difficulties. The present exploratory study examined how two subgroups of students with LD in inclusive settings, students with high and low social status, perceive social situations. Using a sociometric technique, three students with LD receiving high social‐status ratings and three students with LD receiving low social‐status ratings were identified. A qualitative approach was used to gather and evaluate data from the participants and their teachers. Results suggested differences between the two subgroups in their (1) sensitivity to cues in the environment, (2) interpretation of social situations in relation to their own experiences, and (3) levels of self‐control. Implications of these findings for practice and future research are discussed. 相似文献
7.
8.
9.
10.
本期推出两篇短小精美的文章,表达了父爱的温馨,有兴趣的读者朋友不妨将它们作为范文来诵渎。 相似文献