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   1857669篇
  免费   149316篇
  国内免费   2960篇
耳鼻咽喉   25455篇
儿科学   61958篇
妇产科学   53675篇
基础医学   267280篇
口腔科学   53879篇
临床医学   164138篇
内科学   360774篇
皮肤病学   39648篇
神经病学   149083篇
特种医学   74802篇
外国民族医学   572篇
外科学   283406篇
综合类   46539篇
现状与发展   4篇
一般理论   728篇
预防医学   142256篇
眼科学   42930篇
药学   139908篇
  2篇
中国医学   3605篇
肿瘤学   99303篇
  2018年   18099篇
  2016年   15775篇
  2015年   18204篇
  2014年   24941篇
  2013年   38269篇
  2012年   51157篇
  2011年   53717篇
  2010年   32185篇
  2009年   30387篇
  2008年   51268篇
  2007年   54238篇
  2006年   54894篇
  2005年   53192篇
  2004年   52476篇
  2003年   49947篇
  2002年   48722篇
  2001年   86322篇
  2000年   89304篇
  1999年   75614篇
  1998年   20537篇
  1997年   18819篇
  1996年   18629篇
  1995年   18252篇
  1994年   17148篇
  1993年   16172篇
  1992年   62150篇
  1991年   60784篇
  1990年   59416篇
  1989年   57630篇
  1988年   53354篇
  1987年   52466篇
  1986年   49916篇
  1985年   48321篇
  1984年   36069篇
  1983年   31033篇
  1982年   18236篇
  1981年   16200篇
  1980年   15272篇
  1979年   34188篇
  1978年   23767篇
  1977年   20143篇
  1976年   18822篇
  1975年   20012篇
  1974年   24361篇
  1973年   23601篇
  1972年   21592篇
  1971年   20334篇
  1970年   18746篇
  1969年   17543篇
  1968年   16152篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Kinase alterations are increasingly recognised as oncogenic drivers in mesenchymal tumours. Infantile fibrosarcoma and the related renal tumour, congenital mesoblastic nephroma, were among the first solid tumours shown to harbour recurrent tyrosine kinase fusions, with the canonical ETV6::NTRK3 fusion identified more than 20 years ago. Although targeted testing has long been used in diagnosis, the advent of more robust sequencing techniques has driven the discovery of kinase alterations in an array of mesenchymal tumours. As our ability to identify these genetic alterations has improved, as has our recognition and understanding of the tumours that harbour these alterations. Specifically, this study will focus upon mesenchymal tumours harbouring NTRK or other kinase alterations, including tumours with an infantile fibrosarcoma-like appearance, spindle cell tumours resembling lipofibromatosis or peripheral nerve sheath tumours and those occurring in adults with a fibrosarcoma-like appearance. As publications describing the histology of these tumours increase so, too, do the variety kinase alterations reported, now including NTRK1/2/3, RET, MET, RAF1, BRAF, ALK, EGFR and ABL1 fusions or alterations. To date, these tumours appear locally aggressive and rarely metastatic, without a clear link between traditional features used in histological grading (e.g. mitotic activity, necrosis) and outcome. However, most of these tumours are amenable to new targeted therapies, making their recognition of both diagnostic and therapeutic import. The goal of this study is to review the clinicopathological features of tumours with NTRK and other tyrosine kinase alterations, discuss the most common differential diagnoses and provide recommendations for molecular confirmation with associated treatment implications.  相似文献   
2.
3.
4.
5.
6.
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   
7.
8.
9.
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   
10.
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