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   4370855篇
  免费   362225篇
  国内免费   15145篇
耳鼻咽喉   61937篇
儿科学   140826篇
妇产科学   114976篇
基础医学   663577篇
口腔科学   118710篇
临床医学   405323篇
内科学   793615篇
皮肤病学   111637篇
神经病学   372180篇
特种医学   171417篇
外国民族医学   753篇
外科学   669802篇
综合类   121244篇
现状与发展   92篇
一般理论   2627篇
预防医学   357563篇
眼科学   102406篇
药学   307617篇
  21篇
中国医学   11812篇
肿瘤学   220090篇
  2021年   55485篇
  2020年   38195篇
  2019年   59517篇
  2018年   77557篇
  2017年   59778篇
  2016年   66182篇
  2015年   78984篇
  2014年   115900篇
  2013年   181338篇
  2012年   127039篇
  2011年   131839篇
  2010年   130283篇
  2009年   133239篇
  2008年   117793篇
  2007年   124424篇
  2006年   133936篇
  2005年   127075篇
  2004年   128011篇
  2003年   117861篇
  2002年   107047篇
  2001年   168284篇
  2000年   163036篇
  1999年   149703篇
  1998年   73063篇
  1997年   68419篇
  1996年   60567篇
  1995年   61229篇
  1994年   54989篇
  1993年   50877篇
  1992年   106574篇
  1991年   101749篇
  1990年   97469篇
  1989年   95031篇
  1988年   87226篇
  1987年   85427篇
  1986年   80347篇
  1985年   78419篇
  1984年   65232篇
  1983年   57905篇
  1982年   46832篇
  1981年   43470篇
  1980年   40677篇
  1979年   54854篇
  1978年   44499篇
  1977年   39611篇
  1976年   36524篇
  1975年   36540篇
  1974年   39441篇
  1973年   37621篇
  1972年   35324篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
31.
32.
Coronavirus disease-19 (COVID-19) caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is now a pandemic threat. This virus is supposed to be spread by human to human transmission. Cellular angiotensin-converting enzyme 2 (ACE2) is the receptor of SARS-CoV-2 which is identical or similar in different species of animals such as pigs, ferrets, cats, orangutans, monkeys, and humans. Moreover, a recent study predicted that dogs might be secondary hosts during the evolution of SARS-CoV-2 from bat to human. Therefore, there is a possibility of spreading SARS-CoV-2 through domestic pets. There are now many reports of SARS-CoV-2 positive cases in dogs, cats, tigers, lion, and minks. Experimental data showed ferrets and cats are highly susceptible to SARS-CoV-2 as infected by virus inoculation and can transmit the virus directly or indirectly by droplets or airborne routes. Based on these natural infection reports and experimental data, whether the pets are responsible for SARS-CoV-2 spread to humans; needs to be deeply investigated. Humans showing clinical symptoms of respiratory infections have been undergoing for the COVID-19 diagnostic test but many infected people and few pets confirmed with SARS-CoV-2 remained asymptomatic. In this review, we summarize the natural cases of SARS-CoV-2 in animals with the latest researches conducted in this field. This review will be helpful to think insights of SARS-CoV-2 transmissions, spread, and demand for seroprevalence studies, especially in companion animals.  相似文献   
33.
34.
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   
35.
36.
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   
37.
38.
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   
39.
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