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   901982篇
  免费   62052篇
  国内免费   26503篇
耳鼻咽喉   9514篇
儿科学   21774篇
妇产科学   16698篇
基础医学   133196篇
口腔科学   18445篇
临床医学   101120篇
内科学   145481篇
皮肤病学   15973篇
神经病学   51962篇
特种医学   33438篇
外国民族医学   277篇
外科学   110855篇
综合类   77528篇
现状与发展   88篇
一般理论   136篇
预防医学   65973篇
眼科学   22555篇
药学   81882篇
  433篇
中国医学   25479篇
肿瘤学   57730篇
  2023年   6120篇
  2022年   16075篇
  2021年   22086篇
  2020年   16716篇
  2019年   15524篇
  2018年   17832篇
  2017年   15758篇
  2016年   15606篇
  2015年   22113篇
  2014年   27967篇
  2013年   29434篇
  2012年   43758篇
  2011年   49085篇
  2010年   31365篇
  2009年   26228篇
  2008年   36963篇
  2007年   38398篇
  2006年   36938篇
  2005年   35359篇
  2004年   28471篇
  2003年   27385篇
  2002年   24697篇
  2001年   30811篇
  2000年   31145篇
  1999年   27190篇
  1998年   10508篇
  1997年   9430篇
  1996年   8336篇
  1995年   7821篇
  1994年   6804篇
  1993年   5646篇
  1992年   16810篇
  1991年   17909篇
  1990年   17716篇
  1989年   17159篇
  1988年   15578篇
  1987年   15364篇
  1986年   14115篇
  1985年   13354篇
  1984年   9751篇
  1983年   8266篇
  1979年   9086篇
  1978年   6451篇
  1976年   5537篇
  1975年   6640篇
  1974年   7459篇
  1973年   7194篇
  1972年   6633篇
  1971年   6330篇
  1970年   5909篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
The present study compared the level of occupational strain and work ability among Han, Hui, Uygur, Hui, and Kazakh teachers, and explored ethnic differences based on the associations of psychosocial factors at work, occupational strain, and work ability. A cross-sectional survey was conducted among 2,941 teachers in primary and secondary schools in Xinjiang Province, China. Psychosocial factors, occupational strain, and work ability were measured using the Occupation Stress Inventory—Revised Edition (OSI-R) and Work Ability Index. Han and Hui teachers experienced reduced work ability compared with Uygur and Kazakh teachers, and this finding was caused, in part, by exposure to psychosocial factors at work. The vocational and psychological strains caused by these factors play an important role in reduced work ability among all ethnic teacher groups. The findings indicate the importance of taking action to reduce occupational strain for promoting teachers' work ability in multiethnic workplaces.  相似文献   
9.
10.
Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs.  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