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   5318229篇
  免费   428566篇
  国内免费   16993篇
耳鼻咽喉   76415篇
儿科学   168945篇
妇产科学   142578篇
基础医学   789692篇
口腔科学   151989篇
临床医学   491150篇
内科学   971984篇
皮肤病学   122551篇
神经病学   447863篇
特种医学   210097篇
外国民族医学   1418篇
外科学   797213篇
综合类   156974篇
现状与发展   25篇
一般理论   2986篇
预防医学   453648篇
眼科学   127821篇
药学   378730篇
  23篇
中国医学   13973篇
肿瘤学   257713篇
  2021年   57182篇
  2019年   59692篇
  2018年   77032篇
  2017年   58708篇
  2016年   65543篇
  2015年   77617篇
  2014年   112757篇
  2013年   178383篇
  2012年   152218篇
  2011年   162016篇
  2010年   133806篇
  2009年   133190篇
  2008年   147222篇
  2007年   158684篇
  2006年   165205篇
  2005年   160213篇
  2004年   160186篇
  2003年   149716篇
  2002年   138687篇
  2001年   210317篇
  2000年   208971篇
  1999年   185733篇
  1998年   78954篇
  1997年   73057篇
  1996年   70984篇
  1995年   66854篇
  1994年   60803篇
  1993年   56351篇
  1992年   139526篇
  1991年   134304篇
  1990年   128830篇
  1989年   124511篇
  1988年   115465篇
  1987年   113698篇
  1986年   107563篇
  1985年   104950篇
  1984年   85113篇
  1983年   74727篇
  1982年   54867篇
  1981年   50571篇
  1980年   47540篇
  1979年   76877篇
  1978年   59375篇
  1977年   51376篇
  1976年   48142篇
  1975年   48652篇
  1974年   56326篇
  1973年   54262篇
  1972年   51072篇
  1971年   47064篇
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
31.
32.
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   
33.
34.
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   
35.
36.
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   
37.
38.
39.
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   
40.
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   
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