首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   122545篇
  免费   1865篇
  国内免费   238篇
教育   85444篇
科学研究   13386篇
各国文化   1989篇
体育   9308篇
综合类   182篇
文化理论   1079篇
信息传播   13260篇
  2021年   959篇
  2020年   1674篇
  2019年   2596篇
  2018年   3080篇
  2017年   3361篇
  2016年   3395篇
  2015年   2324篇
  2014年   3208篇
  2013年   27391篇
  2012年   2365篇
  2011年   2678篇
  2010年   2340篇
  2009年   2624篇
  2008年   2365篇
  2007年   2073篇
  2006年   2327篇
  2005年   2326篇
  2004年   3001篇
  2003年   2343篇
  2002年   2165篇
  2001年   2032篇
  2000年   1675篇
  1999年   1555篇
  1998年   1458篇
  1997年   1528篇
  1996年   1692篇
  1995年   1465篇
  1994年   1468篇
  1993年   1467篇
  1992年   1486篇
  1991年   1398篇
  1990年   1386篇
  1989年   1323篇
  1988年   1181篇
  1987年   1087篇
  1986年   1135篇
  1985年   1397篇
  1984年   1269篇
  1983年   1262篇
  1982年   1250篇
  1981年   1167篇
  1980年   1162篇
  1979年   1246篇
  1978年   1201篇
  1977年   1118篇
  1976年   992篇
  1975年   801篇
  1974年   809篇
  1973年   775篇
  1971年   619篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
811.
812.
813.
814.
What If?     
  相似文献   
815.
With the rise of microfluidics for the past decade, there has come an ever more pressing need for a low-cost and rapid prototyping technology, especially for research and education purposes. In this article, we report a rapid prototyping process of chromed masks for various microfluidic applications. The process takes place out of a clean room, uses a commercially available video-projector, and can be completed in less than half an hour. We quantify the ranges of fields of view and of resolutions accessible through this video-projection system and report the fabrication of critical microfluidic components (junctions, straight channels, and curved channels). To exemplify the process, three common devices are produced using this method: a droplet generation device, a gradient generation device, and a neuro-engineering oriented device. The neuro-engineering oriented device is a compartmentalized microfluidic chip, and therefore, required the production and the precise alignment of two different masks.  相似文献   
816.
817.
The authors examined the relationship between stress, adaptive coping, and life satisfaction among college students who reported having a friend or family member with eating disorder symptomatology. A hierarchical regression confirmed the study's hypotheses. Higher stress was linked with less life satisfaction. After stress was controlled, plan coping had a beneficial influence on life satisfaction. College counselors can use these findings when choosing interventions for clients who are close to someone with an eating disorder.  相似文献   
818.
Editorial     
B. Sury 《Resonance》2017,22(5):431-432
  相似文献   
819.
820.
IntroductionWhile early commenting on studies is seen as one of the advantages of preprints, the type of such comments, and the people who post them, have not been systematically explored.Materials and methodsWe analysed comments posted between 21 May 2015 and 9 September 2019 for 1983 bioRxiv preprints that received only one comment on the bioRxiv website. The comment types were classified by three coders independently, with all differences resolved by consensus.ResultsOur analysis showed that 69% of comments were posted by non-authors (N = 1366), and 31% by the preprints’ authors themselves (N = 617). Twelve percent of non-author comments (N = 168) were full review reports traditionally found during journal review, while the rest most commonly contained praises (N = 577, 42%), suggestions (N = 399, 29%), or criticisms (N = 226, 17%). Authors’ comments most commonly contained publication status updates (N = 354, 57%), additional study information (N = 158, 26%), or solicited feedback for the preprints (N = 65, 11%).ConclusionsOur results indicate that comments posted for bioRxiv preprints may have potential benefits for both the public and the scholarly community. Further research is needed to measure the direct impact of these comments on comments made by journal peer reviewers, subsequent preprint versions or journal publications.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号