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   4252558篇
  免费   361272篇
  国内免费   15121篇
耳鼻咽喉   61099篇
儿科学   133203篇
妇产科学   112120篇
基础医学   652235篇
口腔科学   118896篇
临床医学   385864篇
内科学   767411篇
皮肤病学   103503篇
神经病学   365490篇
特种医学   170964篇
外国民族医学   913篇
外科学   652419篇
综合类   126006篇
现状与发展   23篇
一般理论   2612篇
预防医学   357876篇
眼科学   100446篇
药学   302186篇
  19篇
中国医学   11247篇
肿瘤学   204419篇
  2021年   54001篇
  2020年   35528篇
  2019年   58675篇
  2018年   73370篇
  2017年   55671篇
  2016年   62042篇
  2015年   75220篇
  2014年   110049篇
  2013年   175441篇
  2012年   119301篇
  2011年   122496篇
  2010年   123370篇
  2009年   126319篇
  2008年   109555篇
  2007年   116253篇
  2006年   125725篇
  2005年   120835篇
  2004年   121721篇
  2003年   112299篇
  2002年   102887篇
  2001年   154333篇
  2000年   150471篇
  1999年   139566篇
  1998年   71293篇
  1997年   67431篇
  1996年   59738篇
  1995年   60935篇
  1994年   55135篇
  1993年   51145篇
  1992年   103165篇
  1991年   98863篇
  1990年   93897篇
  1989年   91503篇
  1988年   85067篇
  1987年   83603篇
  1986年   79294篇
  1985年   77755篇
  1984年   65646篇
  1983年   58456篇
  1982年   47699篇
  1981年   44435篇
  1980年   41705篇
  1979年   57474篇
  1978年   46700篇
  1977年   41154篇
  1976年   38280篇
  1975年   37537篇
  1974年   42186篇
  1973年   40358篇
  1972年   37923篇
排序方式: 共有10000条查询结果,搜索用时 15 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