全文获取类型
收费全文 | 20405篇 |
免费 | 202篇 |
国内免费 | 25篇 |
专业分类
教育 | 14089篇 |
科学研究 | 2389篇 |
各国文化 | 139篇 |
体育 | 1606篇 |
综合类 | 9篇 |
文化理论 | 243篇 |
信息传播 | 2157篇 |
出版年
2021年 | 167篇 |
2020年 | 246篇 |
2019年 | 348篇 |
2018年 | 1146篇 |
2017年 | 1127篇 |
2016年 | 887篇 |
2015年 | 346篇 |
2014年 | 476篇 |
2013年 | 2993篇 |
2012年 | 460篇 |
2011年 | 683篇 |
2010年 | 613篇 |
2009年 | 457篇 |
2008年 | 549篇 |
2007年 | 627篇 |
2006年 | 323篇 |
2005年 | 361篇 |
2004年 | 416篇 |
2003年 | 354篇 |
2002年 | 282篇 |
2001年 | 338篇 |
2000年 | 346篇 |
1999年 | 314篇 |
1998年 | 163篇 |
1997年 | 201篇 |
1996年 | 210篇 |
1995年 | 150篇 |
1994年 | 188篇 |
1993年 | 149篇 |
1992年 | 302篇 |
1991年 | 262篇 |
1990年 | 246篇 |
1989年 | 268篇 |
1988年 | 232篇 |
1987年 | 208篇 |
1986年 | 235篇 |
1985年 | 235篇 |
1984年 | 184篇 |
1983年 | 214篇 |
1982年 | 164篇 |
1981年 | 171篇 |
1980年 | 152篇 |
1979年 | 257篇 |
1978年 | 170篇 |
1977年 | 166篇 |
1976年 | 159篇 |
1975年 | 126篇 |
1974年 | 144篇 |
1973年 | 115篇 |
1971年 | 109篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
133.
Rocío Cupeiro Miguel A. Rojo-Tirado Cristina Cadenas-Sanchez Enrique G. Artero Ana B. Peinado Idoia Labayen 《Journal of sports sciences》2020,38(13):1506-1515
ABSTRACT The aim of the present study was to investigate the existence of a relative age effect (RAE) on physical fitness of preschoolers. Anthropometry and physical fitness were assessed in 3147 children (3–5 years old) using the PREFIT battery. Based on the birth year, participants were divided into 3year groups (3-, 4- and 5-years). Within each year group, 4quarter groups were created: quarter 1, preschoolers born from January to March; quarter 2, from April to June; quarter 3, from July to September; quarter 4, from October to December. The MANCOVA analysis revealed a main effect of year group (Wilks’ λ = 0.383; F10,5996 = 369.64; p < 0.001, ηp 2 = 0.381) and of quarter (Wilks’ λ = 0.874; F15,8276.6 = 27.67; p < 0.001; ηp 2 = 0.044) over the whole battery of tests. To the best of our knowledge, this is the first study to report the existence of RAE at the preschool stage. In general, performance improved as the relative age increased (i.e., those born in quarter 1 performed better than those in the other quarters). Individualization strategies should be addressed within the same academic year not only in elementary or secondary years but also in preschoolers. 相似文献
134.
135.
136.
Dylan J.H.A. Henssen Loes van den Heuvel Guido De Jong Marc A.T.M. Vorstenbosch Anne-Marie van Cappellen van Walsum Marianne M. Van den Hurk Jan G.M. Kooloos Ronald H.M.A. Bartels 《Anatomical sciences education》2020,13(3):353-365
Neuroanatomy education is a challenging field which could benefit from modern innovations, such as augmented reality (AR) applications. This study investigates the differences on test scores, cognitive load, and motivation after neuroanatomy learning using AR applications or using cross-sections of the brain. Prior to two practical assignments, a pretest (extended matching questions, double-choice questions and a test on cross-sectional anatomy) and a mental rotation test (MRT) were completed. Sex and MRT scores were used to stratify students over the two groups. The two practical assignments were designed to study (1) general brain anatomy and (2) subcortical structures. Subsequently, participants completed a posttest similar to the pretest and a motivational questionnaire. Finally, a focus group interview was conducted to appraise participants’ perceptions. Medical and biomedical students (n = 31); 19 males (61.3%) and 12 females (38.7%), mean age 19.2 ± 1.7 years participated in this experiment. Students who worked with cross-sections (n = 16) showed significantly more improvement on test scores than students who worked with GreyMapp-AR (P = 0.035) (n = 15). Further analysis showed that this difference was primarily caused by significant improvement on the cross-sectional questions. Students in the cross-section group, moreover, experienced a significantly higher germane (P = 0.009) and extraneous cognitive load (P = 0.016) than students in the GreyMapp-AR group. No significant differences were found in motivational scores. To conclude, this study suggests that AR applications can play a role in future anatomy education as an add-on educational tool, especially in learning three-dimensional relations of anatomical structures. 相似文献
137.
Bahar Köymen Cathal O’Madagain Andreas Domberg Michael Tomasello 《Child development》2020,91(3):685-693
In collaborative problem solving, children produce and evaluate arguments for proposals. We investigated whether 3- and 5-year-olds (N = 192) can produce and evaluate arguments against those arguments (i.e., counter-arguments). In Study 1, each child within a peer dyad was privately given a reason to prefer one over another solution to a task. One child, however, was given further information that would refute the reasoning of their partner. Five-year-olds, but not 3-year-olds, identified and produced valid and relevant counter-arguments. In Study 2, 3-year-olds were given discourse training (discourse that contrasted valid and invalid counter-arguments) and then given the same problem-solving tasks. After training, 3-year-olds could also identify and produce valid and relevant counter-arguments. Thus, participating in discourse about reasons facilitates children’s counter-argumentation. 相似文献
138.
This paper demonstrates the application of module arithmetic for controlling the level of information security by a new technique referred as integer splitting. The basic definitions and concepts of the method are provided. The mathematical function of arising transformation is described in detail; its properties were studied and the basic theorems were proven that justify the use of splitting in practical applications. An active system was designed and characteristic cases of its operation are considered. 相似文献
139.
A Campus-Wide Investigation of Clicker Implementation: The Status of Peer Discussion in STEM Classes
Justin D. Lewin Erin L. Vinson MacKenzie R. Stetzer Michelle K. Smith 《CBE life sciences education》2016,15(1)
At the University of Maine, middle and high school teachers observed more than 250 university science, technology, engineering, and mathematics classes and collected information on the nature of instruction, including how clickers were being used. Comparisons of classes taught with (n = 80) and without (n = 184) clickers show that, while instructional behaviors differ, the use of clickers alone does not significantly impact the time instructors spend lecturing. One possible explanation stems from the observation of three distinct modes of clicker use: peer discussion, in which students had the opportunity to talk with one another during clicker questions; individual thinking, in which no peer discussion was observed; and alternative collaboration, in which students had time for discussion, but it was not paired with clicker questions. Investigation of these modes revealed differences in the range of behaviors, the amount of time instructors lecture, and how challenging the clicker questions were to answer. Because instructors can vary their instructional style from one clicker question to the next, we also explored differences in how individual instructors incorporated peer discussion during clicker questions. These findings provide new insights into the range of clicker implementation at a campus-wide level and how such findings can be used to inform targeted professional development for faculty. 相似文献
140.