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   615520篇
  免费   33783篇
  国内免费   1218篇
耳鼻咽喉   7712篇
儿科学   19526篇
妇产科学   14621篇
基础医学   104204篇
口腔科学   14361篇
临床医学   55551篇
内科学   114239篇
皮肤病学   13629篇
神经病学   42044篇
特种医学   23137篇
外国民族医学   78篇
外科学   90235篇
综合类   9223篇
现状与发展   2篇
一般理论   153篇
预防医学   43631篇
眼科学   13308篇
药学   48505篇
  4篇
中国医学   1613篇
肿瘤学   34745篇
  2021年   5508篇
  2019年   5364篇
  2018年   7554篇
  2017年   5543篇
  2016年   6345篇
  2015年   7090篇
  2014年   9375篇
  2013年   13805篇
  2012年   19924篇
  2011年   21940篇
  2010年   12950篇
  2009年   11489篇
  2008年   19777篇
  2007年   21656篇
  2006年   20990篇
  2005年   20126篇
  2004年   20029篇
  2003年   19290篇
  2002年   18866篇
  2001年   25675篇
  2000年   26146篇
  1999年   21513篇
  1998年   6252篇
  1997年   5176篇
  1996年   5137篇
  1995年   4814篇
  1992年   15976篇
  1991年   17410篇
  1990年   17283篇
  1989年   16920篇
  1988年   15511篇
  1987年   15271篇
  1986年   14233篇
  1985年   13618篇
  1984年   10088篇
  1983年   8636篇
  1982年   4601篇
  1979年   9457篇
  1978年   6778篇
  1977年   5501篇
  1976年   5822篇
  1975年   7005篇
  1974年   7860篇
  1973年   7590篇
  1972年   6995篇
  1971年   6680篇
  1970年   6209篇
  1969年   5798篇
  1968年   5477篇
  1967年   4908篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
ABSTRACT

Purpose

To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163+ M2 macrophages in proliferative diabetic retinopathy (PDR).  相似文献   
22.
23.
24.
25.
26.
27.
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   
28.
Guidelines and consensus on the management of patients with acne aim to give evidence-based, expert-group recommendations. This review compares current guidelines and consensus articles to provide a compilation of recommendations on the treatment of acne with oral isotretinoin. Ten common, relevant, clinical questions are addressed, based on published recommendations, including the indications of isotretinoin, the proposed daily dose, the cumulative isotretinoin dose and the laboratory monitoring needed. Recommendations on special considerations are also addressed, including the timing of procedures and the question of an association of depression or inflammatory bowel disease with isotretinoin. A major limitation is the use of different classification systems for acne across guidelines. The recommended daily dose ranges from 0.3 to 0.5 mg/kg in the European guidelines to up to 1 mg/kg in the US guidelines. A specific duration of treatment of at least 6 months is only recommended in the European guidelines. All guidelines report the need of strict pregnancy prevention measures. The European, French and US guidelines recommend to monitor for symptoms of depression. Important clinical questions that are inconsistently addressed in guidelines include the age indication, the recommendation for a cumulative dose, the timing of procedures, the association of isotretinoin with IBD, the recommendation for preventing acne flares and for appropriate laboratory monitoring. These topics should be clearly included in the recommendations of guidelines as they are often raised in everyday clinical practice.  相似文献   
29.
30.
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