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   3524991篇
  免费   295106篇
  国内免费   14638篇
耳鼻咽喉   49030篇
儿科学   108109篇
妇产科学   92075篇
基础医学   552779篇
口腔科学   97635篇
临床医学   313824篇
内科学   627022篇
皮肤病学   93604篇
神经病学   302193篇
特种医学   140479篇
外国民族医学   461篇
外科学   550524篇
综合类   107819篇
现状与发展   24篇
一般理论   2299篇
预防医学   288193篇
眼科学   80929篇
药学   246524篇
  23篇
中国医学   10403篇
肿瘤学   170786篇
  2021年   55344篇
  2020年   35346篇
  2019年   58392篇
  2018年   71581篇
  2017年   54607篇
  2016年   60414篇
  2015年   74440篇
  2014年   108756篇
  2013年   174172篇
  2012年   94327篇
  2011年   94043篇
  2010年   116830篇
  2009年   121633篇
  2008年   81081篇
  2007年   84939篇
  2006年   95474篇
  2005年   90600篇
  2004年   92492篇
  2003年   83766篇
  2002年   73709篇
  2001年   109816篇
  2000年   102927篇
  1999年   101807篇
  1998年   65439篇
  1997年   63305篇
  1996年   60787篇
  1995年   56221篇
  1994年   50445篇
  1993年   47123篇
  1992年   72030篇
  1991年   68334篇
  1990年   65282篇
  1989年   64636篇
  1988年   60474篇
  1987年   59092篇
  1986年   56584篇
  1985年   56183篇
  1984年   50661篇
  1983年   45924篇
  1982年   42410篇
  1981年   39852篇
  1980年   37708篇
  1979年   43067篇
  1978年   37464篇
  1977年   34356篇
  1976年   31115篇
  1975年   30766篇
  1974年   32535篇
  1973年   31169篇
  1972年   29592篇
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
31.
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   
32.
33.
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   
34.
35.
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   
36.
37.
38.
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   
39.
Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.  相似文献   
40.
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