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   1539932篇
  免费   113278篇
  国内免费   7482篇
耳鼻咽喉   20143篇
儿科学   50317篇
妇产科学   40574篇
基础医学   221959篇
口腔科学   41379篇
临床医学   147483篇
内科学   289073篇
皮肤病学   31450篇
神经病学   126364篇
特种医学   58047篇
外国民族医学   387篇
外科学   214771篇
综合类   45853篇
现状与发展   8篇
一般理论   496篇
预防医学   128193篇
眼科学   33470篇
药学   116365篇
  96篇
中国医学   9052篇
肿瘤学   85212篇
  2021年   14169篇
  2019年   13719篇
  2018年   19886篇
  2017年   15932篇
  2016年   17282篇
  2015年   20563篇
  2014年   27172篇
  2013年   40389篇
  2012年   56896篇
  2011年   59499篇
  2010年   36272篇
  2009年   32765篇
  2008年   54225篇
  2007年   57271篇
  2006年   56919篇
  2005年   54765篇
  2004年   51536篇
  2003年   48704篇
  2002年   47143篇
  2001年   67174篇
  2000年   68633篇
  1999年   57093篇
  1998年   16019篇
  1997年   14446篇
  1996年   14016篇
  1995年   13204篇
  1994年   12317篇
  1993年   11557篇
  1992年   43552篇
  1991年   42691篇
  1990年   41293篇
  1989年   39153篇
  1988年   36122篇
  1987年   35260篇
  1986年   33582篇
  1985年   32043篇
  1984年   24144篇
  1983年   20464篇
  1982年   12354篇
  1979年   22016篇
  1978年   15699篇
  1977年   12800篇
  1976年   12511篇
  1975年   13030篇
  1974年   15778篇
  1973年   15378篇
  1972年   14256篇
  1971年   13287篇
  1970年   12243篇
  1969年   11142篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
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   
12.
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   
13.
14.
目的:探讨牙支持式3D打印导板辅助穿刺卵圆孔射频热凝治疗三叉神经痛术中术后的疗效分析.方法:对2019年1月~2021年5月收治的三叉神经痛患者40人,根据患者需要随机分成2组:A组(对照组),常规按照Hartel前入路法穿刺卵圆孔,进入卵圆孔后,耳-床线定位确定入颅深度后行射频治疗.B组(导板组),采用3D导板,给患者戴上导板固定后,完成穿刺,耳-床线定位确定入颅深度后行射频治疗.分析2组的术前疼痛评分(VAS)术后即刻及术后1月疼痛消失的有效率,手术时间,穿刺次数,并发症,穿刺的偏移程度.结果:与对照组A组比较在术后即刻有效率、术后1月随访有效率比较无统计学差异(P>0.05).在穿刺次数、穿刺偏移率、手术时间、并发症两组间比较有统计学差异(P<0.05).导板与牙齿紧密贴合率100%.结论:3D打印导板应用于穿刺卵圆孔具有明显的优势,可以减少患者创伤,减少X线辐射,减少穿刺偏移,术后疗效肯定,值得广泛应用.  相似文献   
15.
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   
16.
17.
18.
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   
19.
20.
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