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   530507篇
  免费   27601篇
  国内免费   494篇
耳鼻咽喉   6693篇
儿科学   16933篇
妇产科学   12544篇
基础医学   92652篇
口腔科学   12359篇
临床医学   48565篇
内科学   95520篇
皮肤病学   11869篇
神经病学   34026篇
特种医学   19772篇
外国民族医学   53篇
外科学   78112篇
综合类   7633篇
现状与发展   2篇
一般理论   107篇
预防医学   38600篇
眼科学   11944篇
药学   41440篇
  1篇
中国医学   1126篇
肿瘤学   28651篇
  2021年   3897篇
  2018年   5740篇
  2017年   4132篇
  2016年   4873篇
  2015年   5364篇
  2014年   7122篇
  2013年   10512篇
  2012年   15601篇
  2011年   17408篇
  2010年   9965篇
  2009年   8840篇
  2008年   15730篇
  2007年   17459篇
  2006年   16952篇
  2005年   16269篇
  2004年   15899篇
  2003年   15284篇
  2002年   14795篇
  2001年   22437篇
  2000年   22981篇
  1999年   18934篇
  1998年   5236篇
  1997年   4365篇
  1996年   4403篇
  1995年   4127篇
  1992年   14422篇
  1991年   15832篇
  1990年   15958篇
  1989年   15640篇
  1988年   14316篇
  1987年   14214篇
  1986年   13177篇
  1985年   12699篇
  1984年   9404篇
  1983年   8004篇
  1982年   4181篇
  1979年   8942篇
  1978年   6383篇
  1977年   5155篇
  1976年   5509篇
  1975年   6616篇
  1974年   7423篇
  1973年   7163篇
  1972年   6601篇
  1971年   6310篇
  1970年   5887篇
  1969年   5468篇
  1968年   5163篇
  1967年   4622篇
  1966年   3963篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Journal of Immigrant and Minority Health - COVID-19 has disproportionally affected underrepresented minorities (URM) and low-income immigrants in the United States. The aim of the study is to...  相似文献   
3.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
4.
Bulletin of Experimental Biology and Medicine - Ammonium, an end-product of catabolism, in low doses can promote adaptation of metabolic pathways in erythrocytes under conditions of extreme...  相似文献   
5.
6.
7.
Pharmaceutical Chemistry Journal - Three extracts were produced from the above-ground part of the meadowsweet Filipendula ulmaria (L.) Maxim. using water, 40% ethanol, and 70% ethanol. Comparative...  相似文献   
8.
9.
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   
10.
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   
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