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   2551330篇
  免费   181284篇
  国内免费   5650篇
耳鼻咽喉   34214篇
儿科学   85400篇
妇产科学   70243篇
基础医学   364869篇
口腔科学   73880篇
临床医学   228812篇
内科学   492387篇
皮肤病学   58602篇
神经病学   201498篇
特种医学   98556篇
外国民族医学   547篇
外科学   385111篇
综合类   57677篇
现状与发展   4篇
一般理论   894篇
预防医学   190245篇
眼科学   60960篇
药学   185698篇
  9篇
中国医学   6044篇
肿瘤学   142614篇
  2019年   19706篇
  2018年   29305篇
  2017年   22466篇
  2016年   25310篇
  2015年   28800篇
  2014年   38999篇
  2013年   57767篇
  2012年   79480篇
  2011年   83391篇
  2010年   49503篇
  2009年   45888篇
  2008年   78073篇
  2007年   83343篇
  2006年   84087篇
  2005年   81131篇
  2004年   78541篇
  2003年   75041篇
  2002年   72524篇
  2001年   125216篇
  2000年   128204篇
  1999年   106864篇
  1998年   28956篇
  1997年   25509篇
  1996年   25301篇
  1995年   24215篇
  1994年   22304篇
  1993年   20710篇
  1992年   81450篇
  1991年   79039篇
  1990年   76612篇
  1989年   73772篇
  1988年   67040篇
  1987年   66088篇
  1986年   62169篇
  1985年   59315篇
  1984年   43944篇
  1983年   37245篇
  1982年   21580篇
  1981年   19335篇
  1979年   39583篇
  1978年   27880篇
  1977年   23770篇
  1976年   22132篇
  1975年   23511篇
  1974年   28375篇
  1973年   27261篇
  1972年   25299篇
  1971年   23474篇
  1970年   21805篇
  1969年   20410篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Low molecular weight heparins are widely used in the prophylaxis and treatment of thrombotic disorders. The effect of low molecular weight heparins on coagulation was examined ultrastructurally in an animal model. A test and a control group was formed, each consisting of five rabbits. Nadroparine (225 Institute of Chaoy Unit/kg twice daily) was applied to the test group for 10 days. The control group received 1 ml saline solution subcutaneously. Blood and vascular tissue samples collected at the end of the 10th day were evaluated under a JEM 100 B electron microscope. Platelet degranulation and agglutination was observed in the control group. Fibrin materials were detected in the cytoplasms and surroundings of degranulated platelets. Erythrocyte accumulation was remarkable on the vascular endothelium with intact coagulation periods. In the test group, outer membranes of platelets, hyalomere, and granular structures in the granulomeres were detected to be nearly intact. There were rare erythrocytes in the large vascular lumens. The aggregation phase had occurred but no agglutination was detected. Nadroparine seems to preserve consistency of lipoprotein membranes of platelets and granular structures containing enzymes, which contribute to the coagulation mechanisms.  相似文献   
33.
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy.  相似文献   
34.
35.
36.
37.
38.
AIM: The innovations for disease management need to be thoroughly evaluated so that their benefits and potential downsides can be compared with the already existing approaches. Endovascular laser (EVL) treatment for varicose veins offers today several advantages over surgical standard stripping. The Italian Endovenous-laser Working Group (IEWG) is a homogeneous group of surgeons and phlebologists who have been using EVL since 1999 and has undertaken to examine EVL in a multicenter study starting from a well defined rationale, with the benefit of a single protocol to use. METHODS: In a cooperative, multicenter, clinical study, 1076 limbs in 1050 patients, mean age of 54.5 years, 241 males and 809 females affected by chronic venous insufficiency (CVI) were considered eligible for surgery and stratified by CEAP classification in a four-year period (January 1999 December 2003). Inclusion criteria were insufficiency of the great and/or small saphenous vein at various levels, beyond those accessory saphenous trunks with incompetence in the saphenofemoral junction. In all cases truncular reflux apparead up on duplex scan examination, with or without associated varicosities. All the patients underwent a surgery on the basis of the clinical assessment. All the centres involved performed treatment in conformity with the Food and Drug Administration (FDA) validated procedure, using an endo-laser venous system kit with a 810-980 nm diode. Duplex scan was performed in all patients after 36 months with very few lost to follow-up cases. RESULTS: In the immediate postoperative period the results have been impressive, with a very effective closure of incompetent great saphenous vein and the other treated varicose veins (the early occlusion rate has been 99%). Major complications have not been detected: in particular, no deep venous thrombosis (DVT) evaluated duplex ultrasound. The patients' acceptability and satisfaction regarding the procedure, have been measured by means of a questionnaire on the quality of life, and the result was 96.7%. After 36 months, the total occusion rate of saphenous trunks has been 97%. CONCLUSIONS: The first important Italian experience with EVL based on preoperative, perioperative and postoperative duplex control and which is also based on the patients' satisfaction at mid/long-term has indicated some advantages over the standard treatment with the stripping method. In terms of reduced postoperative pain, shorter sick leave, a faster resumption of the normal activities, and, in particular, the total absence of DVT, we can conclude that EVL is a good solution for all patients with anatomic and hemodinamic patterns for saphenous vein surgery.  相似文献   
39.
Abstrakt 1. Ein nicht ausgefülltes und nicht unterschriebenes Aufkl?rungsformular in der Krankenakte bildet ein Indiz nicht für, sondern gegen die Durchführung eines Aufkl?rungsgespr?chs. 2. Wenn vor dem ?rztlichen Eingriff überhaupt keine Aufkl?rung erfolgt, genügt für den Beginn der Verj?hrung eines auf eine Aufkl?rungspflichtverletzung gestützten Anspruchs die Kenntnis vom Eintritt schwerwiegender Komplikationen. Nicht erforderlich ist das Wissen, dass sich ein typisches Risiko des Eingriffs verwirklicht hat.  相似文献   
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