全文获取类型
收费全文 | 38750篇 |
免费 | 741篇 |
国内免费 | 448篇 |
专业分类
教育 | 24970篇 |
科学研究 | 5472篇 |
各国文化 | 316篇 |
体育 | 2856篇 |
综合类 | 818篇 |
文化理论 | 236篇 |
信息传播 | 5271篇 |
出版年
2022年 | 318篇 |
2021年 | 708篇 |
2020年 | 702篇 |
2019年 | 769篇 |
2018年 | 982篇 |
2017年 | 1013篇 |
2016年 | 913篇 |
2015年 | 922篇 |
2014年 | 1435篇 |
2013年 | 5489篇 |
2012年 | 1804篇 |
2011年 | 1955篇 |
2010年 | 1725篇 |
2009年 | 1615篇 |
2008年 | 1685篇 |
2007年 | 1740篇 |
2006年 | 1674篇 |
2005年 | 1477篇 |
2004年 | 903篇 |
2003年 | 862篇 |
2002年 | 837篇 |
2001年 | 921篇 |
2000年 | 638篇 |
1999年 | 612篇 |
1998年 | 396篇 |
1997年 | 344篇 |
1996年 | 344篇 |
1995年 | 324篇 |
1994年 | 247篇 |
1993年 | 261篇 |
1992年 | 379篇 |
1991年 | 330篇 |
1990年 | 319篇 |
1989年 | 319篇 |
1988年 | 273篇 |
1987年 | 304篇 |
1986年 | 279篇 |
1985年 | 314篇 |
1984年 | 245篇 |
1983年 | 208篇 |
1982年 | 180篇 |
1981年 | 157篇 |
1980年 | 134篇 |
1979年 | 242篇 |
1978年 | 174篇 |
1977年 | 153篇 |
1976年 | 137篇 |
1975年 | 130篇 |
1974年 | 134篇 |
1971年 | 119篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
1.
Research in Higher Education - Given the significant need to increase and diversify graduate enrollments within computing fields, it is vital to understand what shapes students’ pathways to... 相似文献
2.
[目的/意义] 探索构建文献情报大数据知识资源体系,支撑面向多领域的智慧知识服务。[方法/过程] 基于AI应用需求,借鉴业界经验,梳理现有资源体系的问题,从多层次多维度扩展资源体系;构建可靠数据处理流程和计算平台,支持高效数据采集和处理;研发智能化数据治理工具,实现知识资源的有效治理,确保提供高质量数据资源。[结果/结论] 已初步形成覆盖多类型、多学科的科技文献大数据知识资源体系,构建完成高度自动化的数据采集治理流程,实施多重数据质量控制,积累数亿高质量数据,且为多个知识服务提供数据支撑。 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.
[目的/意义]欧洲阅读联盟是欧洲社会力量开展阅读活动的母平台,联盟成员所开展的阅读活动既有差异,也有共性,社会影响力大。通过对欧洲阅读联盟成员所办阅读活动及其规律的分析,可为我国公共图书馆主导与开展阅读活动提供借鉴。[方法/过程]概述欧洲阅读联盟,对其成员类型进行解析,并对每一成员的阅读项目进行共性分析,凝练出阅读活动的经验及规律。[结果/结论]我国应建立多级阅读推广力量,建立政府购买阅读服务长效机制,开放图书馆的阅读活动空间,提升阅读活动频率,开发多样化、差异化的阅读活动。 相似文献
6.
Cultural Studies of Science Education - The retention of underrepresented students remains a significant challenge in the STEM (Science, Technology, Engineering and Math) disciplines. A broad range... 相似文献
7.
8.
9.
10.
U. Casellato F. Fenzi P. Guerriero S. Sitran P. A. Vigato U. Russo M. Galgani M. Mendera A. Manasse 《Journal of Cultural Heritage》2003,4(4):337-353
A significant number of archaeological finds of the 13th–16th century from the Tuscan sites of Germagnana and Gambassi in Valdelsa—FI, was studied by different physico-chemical investigations (SEM–EDS, ICP, Mössbauer spectroscopy, XRD, XRF, TG-DTA) in order to contribute to clarify the production methodology and the pre-industrial glass manufacture technology. The studied samples are mainly non-vitreous finds as production waste, refractory materials, crucibles and raw materials; also vitreous finds as frits, skims, glasses (glass masses, glass working waste and finished products) have been taken into consideration. The obtained petrographic and physico-chemical data strongly suggest that both Gambassi and Germagnana glass manufactures were strictly connected with the sources of vitrifiable materials, situated in Tuscan sand quarries. In particular a comparison between sands from the neighbouring quarries and appropriate finds of the two archaeological sites evidences that the employed vitrifiable materials possibly belong to La Casina La Cava resort. The archaeological classification, based on macroscopic observation and stratigraphic position, was compared and verified with the scientific classification of the examined finds of Germagnana and Gambassi sites based on their composition, morphology and physico-chemical properties. 相似文献