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   2347316篇
  免费   179522篇
  国内免费   5986篇
耳鼻咽喉   32397篇
儿科学   79290篇
妇产科学   64781篇
基础医学   340189篇
口腔科学   63799篇
临床医学   218964篇
内科学   457553篇
皮肤病学   49170篇
神经病学   190509篇
特种医学   89045篇
外国民族医学   912篇
外科学   342037篇
综合类   51963篇
现状与发展   3篇
一般理论   801篇
预防医学   191086篇
眼科学   52214篇
药学   174380篇
  7篇
中国医学   5153篇
肿瘤学   128571篇
  2019年   18809篇
  2018年   26429篇
  2017年   19890篇
  2016年   21735篇
  2015年   24938篇
  2014年   34459篇
  2013年   53069篇
  2012年   72880篇
  2011年   77256篇
  2010年   45586篇
  2009年   42610篇
  2008年   71904篇
  2007年   76499篇
  2006年   76716篇
  2005年   74424篇
  2004年   71672篇
  2003年   68842篇
  2002年   66964篇
  2001年   108179篇
  2000年   111882篇
  1999年   94510篇
  1998年   26723篇
  1997年   24122篇
  1996年   24210篇
  1995年   23015篇
  1994年   21731篇
  1993年   20270篇
  1992年   75656篇
  1991年   74123篇
  1990年   71883篇
  1989年   68478篇
  1988年   63339篇
  1987年   62184篇
  1986年   58618篇
  1985年   56062篇
  1984年   42315篇
  1983年   35813篇
  1982年   21174篇
  1981年   19121篇
  1979年   38127篇
  1978年   26924篇
  1977年   22436篇
  1976年   21509篇
  1975年   22655篇
  1974年   27063篇
  1973年   26312篇
  1972年   24271篇
  1971年   22332篇
  1970年   20942篇
  1969年   18996篇
排序方式: 共有10000条查询结果,搜索用时 26 毫秒
11.
Anaplastic thyroid carcinoma (ATC) is an aggressive thyroid malignancy with high mortality rate. This malignancy arises in thyroid follicular cells either denovo or with an associated differentiated thyroid carcinoma component. Clinically, it usually presents as a rapidly enlarging mass, pain and locally compressive symptoms. Histopathologic variability and heterogeneity often pose diagnostic challenges, especially in scant and paucicellular specimens. This article describes the clinical, histopathologic and molecular features of ATC and also addresses the associated diagnostic limitations and challenges.  相似文献   
12.
Bone mineral density (BMD) is a highly heritable predictor of osteoporotic fracture. GWAS have identified hundreds of loci influencing BMD, but few have been functionally analyzed. In this study, we show that SNPs within a BMD locus on chromosome 14q32.32 alter splicing and expression of PAR-1a/microtubule affinity regulating kinase 3 (MARK3), a conserved serine/threonine kinase known to regulate bioenergetics, cell division, and polarity. Mice lacking Mark3 either globally or selectively in osteoblasts have increased bone mass at maturity. RNA profiling from Mark3-deficient osteoblasts suggested changes in the expression of components of the Notch signaling pathway. Mark3-deficient osteoblasts exhibited greater matrix mineralization compared with controls that was accompanied by reduced Jag1/Hes1 expression and diminished downstream JNK signaling. Overexpression of Jag1 in Mark3-deficient osteoblasts both in vitro and in vivo normalized mineralization capacity and bone mass, respectively. Together, these findings reveal a mechanism whereby genetically regulated alterations in Mark3 expression perturb cell signaling in osteoblasts to influence bone mass.  相似文献   
13.
14.
The coronavirus disease 2019 (COVID-19) pandemic has rapidly created widespread impacts on global health and the economy. Data suggest that women are less susceptible to severe illness. However, sex-disaggregated data are incomplete, leaving room for misinterpretation, and focusing only on biologic sex underestimates the gendered impact of the pandemic on women. This narrative review summarizes what is known about gender disparities during the COVID-19 pandemic and the economic, domestic, and health burdens along with overlapping vulnerabilities related to the pandemic. In addition, this review outlines recommended strategies that advocacy groups, community leaders, and policymakers should implement to mitigate the widening gender disparities related to COVID-19.  相似文献   
15.
16.
17.
The coronavirus 2019 pandemic has affected almost every aspect of health care delivery in the United States, and the emergency medicine system has been hit particularly hard while dealing with this public health crisis. In an unprecedented time in our history, medical systems and clinicians have been asked to be creative, flexible, and innovative, all while continuing to uphold the important standards in the US health care system. To continue providing quality services to patients during this extraordinary time, care providers, organizations, administrators, and insurers have needed to alter longstanding models and procedures to respond to the dynamics of a pandemic. The Emergency Medicine Treatment and Active Labor Act of 1986, or EMTALA, is 1 example of where these alterations have allowed health care facilities and clinicians to continue their work of caring for patients while protecting both the patients and the clinicians themselves from infectious exposures at the same time.  相似文献   
18.
19.
20.
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