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   6664篇
  免费   678篇
  国内免费   48篇
耳鼻咽喉   53篇
儿科学   201篇
妇产科学   169篇
基础医学   846篇
口腔科学   58篇
临床医学   753篇
内科学   1379篇
皮肤病学   200篇
神经病学   464篇
特种医学   510篇
外科学   896篇
综合类   235篇
一般理论   2篇
预防医学   508篇
眼科学   74篇
药学   274篇
  2篇
中国医学   32篇
肿瘤学   734篇
  2022年   46篇
  2021年   118篇
  2020年   76篇
  2019年   94篇
  2018年   78篇
  2017年   103篇
  2016年   88篇
  2015年   125篇
  2014年   178篇
  2013年   215篇
  2012年   303篇
  2011年   316篇
  2010年   231篇
  2009年   235篇
  2008年   248篇
  2007年   286篇
  2006年   298篇
  2005年   261篇
  2004年   279篇
  2003年   265篇
  2002年   239篇
  2001年   231篇
  2000年   228篇
  1999年   179篇
  1998年   154篇
  1997年   121篇
  1996年   110篇
  1995年   96篇
  1994年   72篇
  1993年   91篇
  1992年   127篇
  1991年   129篇
  1990年   106篇
  1989年   132篇
  1988年   139篇
  1987年   126篇
  1986年   129篇
  1985年   104篇
  1984年   77篇
  1983年   80篇
  1982年   65篇
  1981年   35篇
  1980年   43篇
  1979年   50篇
  1978年   52篇
  1977年   34篇
  1976年   41篇
  1975年   38篇
  1955年   43篇
  1954年   38篇
排序方式: 共有7390条查询结果,搜索用时 214 毫秒
1.
2.
3.
4.
Background Beating heart surgery has now become the commonest technique of doing Coronary Artery Bypass Graft Surgery (CABG) in our country. It is being used even in such high risk situations like diffuse coronary disease and Critical Left Main stem Stenosis (LMCS) with good results. The aim of this study is to retrospectively review our results in Off-Pump Coronary Artery Bypass Surgery (OPCAB) in patients with critical left main stem stenosis. Methods This study is a retrospective analysis of the data of patients who underwent primary coronary artery bypass surgery. During the period from April 2003 to September 2005 a total of 64 patients underwent OPCAB procedure for critical LMCS. During the same period 10 patients underwent CABG on Cardio Pulmonary Bypass (CPB). The age range was 36–77yrs. The sex distribution was M: F 53∶10. Ten patients were done as emergency. 2 of them were on Intra Aortic Balloon Pump (IABP) support preoperatively. 10 patients were high risk with a Euro score of ≥5. Results Left Internal Mammary Artery (LIMA) was used in 78% of cases. Average grafts per patient was 2.96. The median ventilation time was 5.91 hrs. New IABP insertion in postoperative period was required in 1 patient. One patient was reexplored for bleeding. There was one perioperative myocardial infarction. 57% of patients did not need any blood transfusion. There was no conversion to CPB. There was no operative mortality. Inotropes were used in ten cases. Conclusions OPCAB is a safe method of revascularization in patients with critical LMCS. Preoperative IABP is useful in patients with cardiogenic shock. However, there is a place for CPB in patients needing additional procedures like Mitral Valve repair (MV repair) or Dor's procedure or when the vessels are very diffusely diseased. Those patients who are unstable despite IABP support may be managed by Beating heart On Pump (BHOP) technique.  相似文献   
5.
6.
7.
8.
BACKGROUND: Despite different available methods for colorectal cancer (CRC) screening and their proven benefits, morbidity, and mortality of this malignancy are still high, partly due to low compliance with screening. Minimally invasive tests based on the analysis of blood specimens may overcome this problem. The purpose of this review was to give an overview of published studies on blood markers aimed at the early detection of CRC and to summarize their performance characteristics. METHOD: The PUBMED database was searched for relevant studies published until June 2006. Only studies with more than 20 cases and more than 20 controls were included. Information on the markers under study, on the underlying study populations, and on performance characteristics was extracted. Special attention was given to performance characteristics by tumor stage. RESULTS: Overall, 93 studies evaluating 70 different markers were included. Most studies were done on protein markers, but DNA markers and RNA markers were also investigated. Performance characteristics varied widely between different markers, but also between different studies using the same marker. Promising results were reported for some novel assays, e.g., assays based on SELDI-TOF MS or MALDI-TOF MS, for some proteins (e.g., soluble CD26 and bone sialoprotein) and also for some genetic assays (e.g., L6 mRNA), but evidence thus far is restricted to single studies with limited sample size and without further external validation. CONCLUSIONS: Larger prospective studies using study populations representing a screening population are needed to verify promising results. In addition, future studies should pay increased attention to the potential of detecting precursor lesions.  相似文献   
9.
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