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   1535篇
  免费   83篇
  国内免费   2篇
耳鼻咽喉   15篇
儿科学   35篇
妇产科学   12篇
基础医学   209篇
口腔科学   21篇
临床医学   93篇
内科学   247篇
皮肤病学   44篇
神经病学   164篇
特种医学   27篇
外国民族医学   1篇
外科学   397篇
综合类   24篇
一般理论   1篇
预防医学   101篇
眼科学   32篇
药学   62篇
中国医学   1篇
肿瘤学   134篇
  2023年   13篇
  2022年   12篇
  2021年   48篇
  2020年   20篇
  2019年   34篇
  2018年   31篇
  2017年   32篇
  2016年   41篇
  2015年   35篇
  2014年   48篇
  2013年   62篇
  2012年   101篇
  2011年   127篇
  2010年   75篇
  2009年   58篇
  2008年   90篇
  2007年   87篇
  2006年   69篇
  2005年   69篇
  2004年   83篇
  2003年   57篇
  2002年   54篇
  2001年   60篇
  2000年   41篇
  1999年   44篇
  1998年   20篇
  1997年   10篇
  1996年   19篇
  1995年   7篇
  1994年   9篇
  1993年   11篇
  1992年   16篇
  1991年   12篇
  1990年   16篇
  1989年   11篇
  1988年   10篇
  1987年   6篇
  1986年   6篇
  1985年   8篇
  1984年   3篇
  1983年   7篇
  1982年   6篇
  1979年   7篇
  1978年   3篇
  1975年   4篇
  1974年   8篇
  1971年   4篇
  1970年   3篇
  1959年   3篇
  1869年   4篇
排序方式: 共有1620条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
Effective height,which represents the height difference between the central free margins and the aortic insertion lines can be easily determined by 2-D echocardiography and allows for identification of prolapse in the native cusps and assessment of prolapse correction after valve repair.Nonetheless,it allows to see only two of three aortic valve(AV)coaptation planes and this may lead to misunderstanding of the underlying pathophysiological mechanism for aortic regurgitation and hence in unsuccessful repair.In contrast,3D transoesophageal echocardiography and multiple plane reconstruction lets visualize all the three coaptation planes between the AV cusps and it represents an invaluable tool in the assessment of aortic valve geometry.It is highly recommendable before AV repair to accurately study the complex three dimensional cusps anatomy and their geometric interrelation with aortic root.  相似文献   
25.
Glycoprotein (GP) IX is a subunit of the von Willebrand receptor, GPIb-V-IX, which mediates adhesion of platelets to the subendothelium of damaged blood vessels. Previous characterization of the GPIX promoter identified a functional Ets site that, when disrupted, reduced promoter activity. However, the Ets protein(s) that regulated GPIX promoter expression was unknown. In this study, transient cotransfection of several GPIX promoter/reporter constructs into 293T kidney fibroblasts with a Fli-1 expression vector shows that the oncogenic protein Fli-1 can transactivate the GPIX promoter when an intact GPIX Ets site is present. In addition, Fli-1 binding of the GPIX Ets site was identified in antibody supershift experiments in nuclear extracts derived from hematopoietic human erythroleukemia cells. Comparative studies showed that Fli-1 was also able to transactivate the GPIbalpha and, to a lesser extent, the GPIIb promoter. Immunoblot analysis identified Fli-1 protein in lysates derived from platelets. In addition, expression of Fli-1 was identified immunohistochemically in megakaryocytes derived from CD34(+) cells treated with the megakaryocyte differentiation and proliferation factor, thrombopoietin. These results suggest that Fli-1 is likely to regulate lineage-specific genes during megakaryocytopoiesis.  相似文献   
26.
27.
28.
29.
Primary sclerosing cholangitis (PCS) is a progressive disease leading to secondary biliary cirrhosis. Patients are at increased risk of developing cholangiocarcinoma, which is usually diagnosed at an advanced stage. Treatment of PCS includes medical therapy, endoscopic biliary dilation, percutaneous transhepatic stenting, extrahepatic biliary resection and liver transplantation. The most effective management of primary sclerosing cholangitis before the onset of cirrhosis remains unclear. Non-transplant surgical procedures have a limited but defined role in patients with PCS. Resection of the extrahepatic biliary tree in symptomatic non-cirrhotic patients improves hyperbilirubinaemia and prolongs both transplant-free and overall survival when compared with non-operative dilation and/or stenting. Surgical resection may also definitively establish or exclude a diagnosis of cholangiocarcinoma in patients with dominant extrahepatic or perihilar strictures. Extrahepatic bile duct resection may also reduce the risk of cholangiocarcinoma. Extrahepatic biliary resection should be considered in selected non-cirrhotic patients with symptomatic biliary obstruction and dominant extrahepatic and/or perihilar strictures. Those patients in whom cholangiocarcinoma is suspected should also undergo resection.  相似文献   
30.
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