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   5447525篇
  免费   422920篇
  国内免费   16459篇
耳鼻咽喉   78747篇
儿科学   172867篇
妇产科学   145270篇
基础医学   805955篇
口腔科学   156846篇
临床医学   501274篇
内科学   994083篇
皮肤病学   126904篇
神经病学   450376篇
特种医学   212343篇
外国民族医学   1301篇
外科学   820895篇
综合类   153100篇
现状与发展   23篇
一般理论   3001篇
预防医学   464539篇
眼科学   131408篇
药学   388545篇
  27篇
中国医学   14151篇
肿瘤学   265249篇
  2021年   58633篇
  2019年   60851篇
  2018年   78761篇
  2017年   60102篇
  2016年   66945篇
  2015年   79177篇
  2014年   114791篇
  2013年   180702篇
  2012年   159577篇
  2011年   171180篇
  2010年   137553篇
  2009年   135341篇
  2008年   154939篇
  2007年   167481篇
  2006年   173536篇
  2005年   167944篇
  2004年   166879篇
  2003年   156176篇
  2002年   145661篇
  2001年   210277篇
  2000年   208411篇
  1999年   186191篇
  1998年   78540篇
  1997年   72428篇
  1996年   70337篇
  1995年   65944篇
  1994年   59944篇
  1993年   55512篇
  1992年   139485篇
  1991年   135413篇
  1990年   130556篇
  1989年   126590篇
  1988年   117380篇
  1987年   115243篇
  1986年   109014篇
  1985年   106508篇
  1984年   85575篇
  1983年   75236篇
  1982年   54679篇
  1981年   50549篇
  1980年   47402篇
  1979年   77676篇
  1978年   59896篇
  1977年   51853篇
  1976年   48911篇
  1975年   50027篇
  1974年   57694篇
  1973年   55286篇
  1972年   52185篇
  1971年   48447篇
排序方式: 共有10000条查询结果,搜索用时 15 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