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   4342775篇
  免费   349578篇
  国内免费   14688篇
耳鼻咽喉   60307篇
儿科学   139409篇
妇产科学   114280篇
基础医学   666602篇
口腔科学   118104篇
临床医学   396407篇
内科学   788883篇
皮肤病学   107818篇
神经病学   368079篇
特种医学   169500篇
外国民族医学   756篇
外科学   656326篇
综合类   121270篇
现状与发展   24篇
一般理论   2617篇
预防医学   358080篇
眼科学   100859篇
药学   307507篇
  23篇
中国医学   11945篇
肿瘤学   218245篇
  2021年   56269篇
  2020年   35885篇
  2019年   58883篇
  2018年   74526篇
  2017年   56699篇
  2016年   62841篇
  2015年   75762篇
  2014年   110044篇
  2013年   175587篇
  2012年   124526篇
  2011年   129244篇
  2010年   125987篇
  2009年   127663篇
  2008年   115372篇
  2007年   122599篇
  2006年   131409篇
  2005年   125476篇
  2004年   126763篇
  2003年   116943篇
  2002年   106150篇
  2001年   166946篇
  2000年   162023篇
  1999年   148680篇
  1998年   71660篇
  1997年   67604篇
  1996年   65627篇
  1995年   61043篇
  1994年   54972篇
  1993年   51015篇
  1992年   106614篇
  1991年   101387篇
  1990年   97240篇
  1989年   94817篇
  1988年   87144篇
  1987年   85308篇
  1986年   80193篇
  1985年   78355篇
  1984年   65395篇
  1983年   58197篇
  1982年   47191篇
  1981年   43855篇
  1980年   41072篇
  1979年   55103篇
  1978年   44758篇
  1977年   39978篇
  1976年   36838篇
  1975年   36805篇
  1974年   39610篇
  1973年   37751篇
  1972年   35358篇
排序方式: 共有10000条查询结果,搜索用时 171 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