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   5797982篇
  免费   444708篇
  国内免费   17108篇
耳鼻咽喉   83712篇
儿科学   185131篇
妇产科学   156473篇
基础医学   849846篇
口腔科学   165882篇
临床医学   538798篇
内科学   1055769篇
皮肤病学   133412篇
神经病学   477764篇
特种医学   225433篇
外国民族医学   1561篇
外科学   869873篇
综合类   166210篇
现状与发展   24篇
一般理论   3153篇
预防医学   493519篇
眼科学   141504篇
药学   414591篇
  27篇
中国医学   15047篇
肿瘤学   282069篇
  2021年   57602篇
  2019年   59883篇
  2018年   78458篇
  2017年   60230篇
  2016年   67202篇
  2015年   78617篇
  2014年   113716篇
  2013年   179464篇
  2012年   168886篇
  2011年   182402篇
  2010年   139573篇
  2009年   136448篇
  2008年   166649篇
  2007年   180726篇
  2006年   186359篇
  2005年   181191篇
  2004年   180329篇
  2003年   169238篇
  2002年   158344篇
  2001年   229881篇
  2000年   229021篇
  1999年   202523篇
  1998年   81259篇
  1997年   74336篇
  1996年   72126篇
  1995年   67758篇
  1994年   61642篇
  1993年   56941篇
  1992年   152076篇
  1991年   147634篇
  1990年   142503篇
  1989年   138172篇
  1988年   128105篇
  1987年   125841篇
  1986年   118894篇
  1985年   115958篇
  1984年   92463篇
  1983年   80933篇
  1982年   57095篇
  1981年   52548篇
  1979年   84562篇
  1978年   64313篇
  1977年   55374篇
  1976年   52326篇
  1975年   53836篇
  1974年   62752篇
  1973年   60347篇
  1972年   57075篇
  1971年   53064篇
  1970年   49685篇
排序方式: 共有10000条查询结果,搜索用时 23 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