全文获取类型
收费全文 | 18071篇 |
免费 | 277篇 |
国内免费 | 55篇 |
专业分类
教育 | 13334篇 |
科学研究 | 1195篇 |
各国文化 | 279篇 |
体育 | 1276篇 |
综合类 | 44篇 |
文化理论 | 89篇 |
信息传播 | 2186篇 |
出版年
2022年 | 108篇 |
2021年 | 192篇 |
2020年 | 256篇 |
2019年 | 381篇 |
2018年 | 548篇 |
2017年 | 583篇 |
2016年 | 540篇 |
2015年 | 353篇 |
2014年 | 493篇 |
2013年 | 3694篇 |
2012年 | 481篇 |
2011年 | 500篇 |
2010年 | 443篇 |
2009年 | 419篇 |
2008年 | 458篇 |
2007年 | 429篇 |
2006年 | 444篇 |
2005年 | 387篇 |
2004年 | 277篇 |
2003年 | 272篇 |
2002年 | 249篇 |
2001年 | 381篇 |
2000年 | 299篇 |
1999年 | 263篇 |
1998年 | 173篇 |
1997年 | 172篇 |
1996年 | 201篇 |
1995年 | 157篇 |
1994年 | 174篇 |
1993年 | 161篇 |
1992年 | 226篇 |
1991年 | 226篇 |
1990年 | 254篇 |
1989年 | 227篇 |
1988年 | 184篇 |
1987年 | 190篇 |
1986年 | 200篇 |
1985年 | 186篇 |
1984年 | 190篇 |
1983年 | 183篇 |
1982年 | 150篇 |
1981年 | 145篇 |
1980年 | 151篇 |
1979年 | 206篇 |
1978年 | 166篇 |
1977年 | 124篇 |
1976年 | 120篇 |
1975年 | 115篇 |
1973年 | 106篇 |
1971年 | 118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.
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.
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
4.
5.
Nancy Burton 《Educational Measurement》1996,15(4):5-9
How has the SAT changed in content and format? Why was it changed? How have changes to the mathematics test affected men's and women's performance? 相似文献
6.
7.
Mike Cass Dennis Cates Michelle Smith Cynthia Jackson 《Learning disabilities research & practice》2003,18(2):112-120
Abstract. A multiple baseline design was employed to test the effect of manipulative instruction on the perimeter and area problem‐solving performance of middle and high school students who had been diagnosed with LD in the area of mathematics. Modeling, prompting/guided practice, and independent practice in conjunction with manipulative training were employed to teach both perimeter and area problem‐solving skills. Analysis of data revealed that the students rapidly acquired the problem‐solving‐skills, maintained these skills over a two‐month period, and transferred these skills to a paper and pencil problem‐solving format. This research extends previous findings by revealing that use of concrete manipulatives promotes the long‐term maintenance of skills. 相似文献
8.
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
9.
G L Zellman 《Child abuse & neglect》1992,16(1):57-74
Drawing distinctions on the basis of at least some case characteristics in making reporting decisions makes considerable sense. Using data from a national survey of mandated reporters that included vignettes in which case and personal characteristics were systematically varied, this paper examines the impact of selected characteristics while controlling for others. The data reveal that respondents noticed and responded to case characteristics. Abuse-relevant judgments and reporting intentions varied, often substantially, as a function of case characteristics. Three case characteristics--previous abuse, severity of abuse, and recantation--were powerful predictors of vignette outcomes. A history of previous abuse led to judgments of greater seriousness, a more salutary impact of a report, and greater likelihood of reporting. More severe abuse was more likely to be labelled as abuse, and was more likely to be reported. When the alleged victim retracted her accusation upon questioning by an authority figure, respondents were significantly less likely to intend a report. Child age, perpetrator intent and family socioeconomic status also influenced abuse-relevant judgments and reporting intentions. Respondents were more likely to intend a report when younger children, lazy or angry perpetrators and children from poorer families were portrayed. 相似文献
10.