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   601篇
  免费   45篇
  国内免费   60篇
耳鼻咽喉   1篇
儿科学   40篇
妇产科学   7篇
基础医学   79篇
口腔科学   18篇
临床医学   101篇
内科学   145篇
皮肤病学   14篇
神经病学   14篇
特种医学   94篇
外科学   35篇
综合类   20篇
预防医学   44篇
眼科学   4篇
药学   49篇
中国医学   2篇
肿瘤学   39篇
  2023年   2篇
  2022年   4篇
  2021年   4篇
  2020年   4篇
  2019年   9篇
  2018年   14篇
  2017年   4篇
  2016年   11篇
  2015年   12篇
  2014年   24篇
  2013年   30篇
  2012年   11篇
  2011年   16篇
  2010年   28篇
  2009年   31篇
  2008年   30篇
  2007年   55篇
  2006年   15篇
  2005年   21篇
  2004年   13篇
  2003年   9篇
  2002年   9篇
  2001年   10篇
  2000年   5篇
  1999年   14篇
  1998年   33篇
  1997年   37篇
  1996年   24篇
  1995年   22篇
  1994年   29篇
  1993年   20篇
  1992年   5篇
  1991年   10篇
  1990年   3篇
  1989年   18篇
  1988年   18篇
  1987年   11篇
  1986年   4篇
  1985年   10篇
  1984年   7篇
  1983年   4篇
  1982年   10篇
  1981年   12篇
  1980年   8篇
  1978年   7篇
  1977年   8篇
  1976年   10篇
  1975年   4篇
  1969年   2篇
  1957年   1篇
排序方式: 共有706条查询结果,搜索用时 109 毫秒
701.

Background  

Preoperative left ventricular dysfunction is an established risk factor for early and late mortality after revascularization. This retrospective analysis demonstrates the effects of preoperative ejection fraction on the short-term and long-term survival of patients after coronary artery bypass grafting.  相似文献   
702.

INTRODUCTION

This study specifically examined right colonic cancer resection, a common operation for colorectal surgeons starting laparoscopic resection, to assess the impact of commencing laparoscopy.

PATIENTS AND METHODS

A total of 56 patients undergoing open (n = 34) and attempted laparoscopic (n = 22) elective right hemicolectomy for colorectal cancer between November 2003 and March 2007 were compared. Postoperative stay was the primary outcome. Secondary outcomes included analgesic requirements, bowel recovery, morbidity and mortality. Frequency of laparoscopic versus open surgery over time was also examined.

RESULTS

Resections attempted laparoscopically increased from 9.1% to 75% in the first and last quarters of the study period, respectively (P = 0.0002). Uptake of ‘enhanced recovery’ was mainly in the laparoscopic group. Conversion was required in two of 22 patients. Attempted laparoscopic cases had a shorter median postoperative stay (6 vs 10 days; P < 0.0001), duration of parenteral or epidural analgesia (48 vs 72 h; P < 0.0001) and time to first bowel action (3 vs 4 days; P = 0.001) compared with open cases. Demography, tumour characteristics, morbidity and mortality were comparable between groups. Multivariate analysis identified decreased age, attempted laparoscopic surgery, use of enhanced recovery and absence of complications as independently shortening postoperative stay.

CONCLUSIONS

Advantages of laparoscopic surgery and enhanced recovery, even early in a surgeon''s experience, suggest this is the preferred mode for elective right colon cancer resection.  相似文献   
703.
AIM: To determine how hepatic entropy and uniformity of computed tomography (CT) images of the liver change after the administration of contrast material and to assess whether these additional parameters are more sensitive to tumour-related changes in the liver than measurements of hepatic attenuation or perfusion. MATERIALS AND METHODS: Hepatic attenuation, entropy, uniformity, and perfusion were measured using multi-phase CT following resection of colorectal cancer. Based on conventional CT and fluorodeoxyglucose positron emission tomography, 12 patients were classified as having no evidence of malignancy, eight with extra-hepatic tumours only, and eight with metastatic liver disease. RESULTS: Hepatic attenuation and entropy increased after CM administration whereas uniformity decreased. Unlike hepatic attenuation, entropy and uniformity changed maximally in the arterial phase. No significant differences in hepatic perfusion or attenuation were found between patient groups, whereas arterial-phase entropy was lower (p=0.034) and arterial-phase uniformity was higher (p=0.034) in apparently disease-free areas of liver in patients with hepatic metastases compared with those with no metastases. CONCLUSION: Temporal changes in hepatic entropy and uniformity differ from those for hepatic attenuation. By reflecting the distribution of hepatic enhancement, these additional parameters are more sensitive to tumour-related changes in the liver than measurements of hepatic attenuation or perfusion.  相似文献   
704.

Introduction  

The high cost of critical care resources has resulted in strategies to reduce the costs of ruling out low-risk patients by developing intermediate care units (IMCs). The aim of this study was to compare changes in total hospital costs for intensive care patients before and after the introduction of an IMC at the University Hospital Maastricht.  相似文献   
705.
RATIONALE AND OBJECTIVES: The acceptance of computer-assisted diagnosis (CAD) in clinical practice has been constrained by the scarcity of identifiable biologic correlates for CAD-based image parameters. This study aims to identify biologic correlates for computed tomography (CT) liver texture in a series of patients with colorectal cancer. MATERIALS AND METHODS: In 28 patients with colorectal cancer, total hepatic perfusion (THP), hepatic arterial perfusion, and hepatic portal perfusion (HPP) were measured using perfusion CT. Hepatic glucose use was also determined from positron emission tomography (PET) and expressed as standardized uptake value (SUV). A hepatic phosphorylation fraction index (HPFI) was determined from both SUV and THP. These physiologic parameters were correlated with CAD parameters namely hepatic densitometry, selective-scale, and relative-scale texture features in apparently normal areas of portal-phase hepatic CT. RESULTS: For patients without liver metastases, a relative-scale texture parameter correlated inversely with SUV (r = -0.587, P = .007) and, positively with THP (r = 0.512, P = .021) and HPP (r = 0.451, P = .046). However, this relative texture parameter correlated most significantly with HPFI (r = -0.590, P = .006). For patients with liver metastases, although not significant an opposite trend was observed between these physiologic parameters and relative texture features (THP: r < -0.4, HPFI: r > 0.35). CONCLUSION: Total hepatic blood flow and glucose metabolism are two distinct but related biologic correlates for liver texture on portal phase CT, providing a rationale for the use of hepatic texture analysis as a indicator for patients with colorectal cancer.  相似文献   
706.

Introduction  

Extracorporeal membrane oxygenation (ECMO) is a supportive cardiopulmonary bypass technique for babies with acute reversible cardiorespiratory failure. We assessed morbidity in ECMO survivors at the age of five years, when they start primary school and major decisions for their school careers must be made.  相似文献   
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