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   4249篇
  免费   330篇
  国内免费   20篇
耳鼻咽喉   21篇
儿科学   146篇
妇产科学   82篇
基础医学   729篇
口腔科学   28篇
临床医学   483篇
内科学   833篇
皮肤病学   58篇
神经病学   395篇
特种医学   148篇
外科学   496篇
综合类   23篇
一般理论   1篇
预防医学   505篇
眼科学   79篇
药学   231篇
中国医学   9篇
肿瘤学   332篇
  2023年   22篇
  2022年   80篇
  2021年   132篇
  2020年   80篇
  2019年   139篇
  2018年   94篇
  2017年   69篇
  2016年   96篇
  2015年   101篇
  2014年   159篇
  2013年   221篇
  2012年   300篇
  2011年   320篇
  2010年   183篇
  2009年   184篇
  2008年   264篇
  2007年   292篇
  2006年   248篇
  2005年   257篇
  2004年   248篇
  2003年   218篇
  2002年   256篇
  2001年   46篇
  2000年   35篇
  1999年   42篇
  1998年   57篇
  1997年   40篇
  1996年   32篇
  1995年   33篇
  1994年   23篇
  1993年   22篇
  1992年   22篇
  1991年   20篇
  1990年   20篇
  1989年   23篇
  1988年   24篇
  1987年   19篇
  1986年   24篇
  1985年   23篇
  1984年   18篇
  1983年   5篇
  1982年   8篇
  1981年   8篇
  1980年   6篇
  1979年   16篇
  1978年   5篇
  1977年   6篇
  1974年   12篇
  1973年   5篇
  1970年   7篇
排序方式: 共有4599条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Despite recent improvement, significant racial disparities in outcome still persist after renal transplantation among African American patients in the United States. This study evaluated the association of race and ethnicity with allograft outcomes in a French population of 952 Caucasian (Cauc) patients and 140 African European (AE) patients who underwent renal transplantation in our center between 1987 and 2003. Demographic characteristics were similar for the two cohorts other than cause of end-stage renal failure (more hypertension among AE and more polycystic kidney disease among Cauc) and cold ischemia time (significantly longer for AE). Immunosuppressive treatment was comparable between groups. There were no significant differences between AE and Cauc in the incidence of acute rejection (31% vs. 30%). At 5 years post-transplant, patient survival (93% vs. 92%), graft survival (83% in both groups) and graft function (creatinine clearance 48 mL/min vs. 45 mL/min) were also similar among the AE and Cauc patients. We demonstrate that ethnic origin does not affect outcome after renal transplantation in France. Therefore, differences observed in the United States cannot be only related to immunologic or pharmacologic factors. The results of renal transplantation in patients of African origin could be improved with universal immunosuppressive drug coverage.  相似文献   
5.
Objective: Generate a list of service guidelines to enable supermarket managers to accommodate the needs of their older customers. Methods: Focus groups and a national telephone survey were conducted with Australian seniors to generate 10 service guidelines for supermarkets. Results: The 10 guidelines produced are considered to be of significant importance by Australian seniors, with some apparent differences in importance and relevance ratings between older and younger seniors, and males and females. Conclusions: Seniors have distinct service preferences when grocery shopping and their needs require special attention in the supermarket environment. In particular, they feel strongly about the quality of staff and equipment with which they come into contact.  相似文献   
6.
INTRODUCTION: Health care workers have long been recognized as having a high risk of work-related assault. In response to a growing threat of violence in hospitals, California implemented the Hospital Security Act (AB508) in 1993. This study compares surveys of emergency nurses before and after implementation of AB508. METHODS: In 1990, the CAL/ENA surveyed emergency departments in California to enumerate violent events and describe security programs. Using the CAL/ENA membership directory, hospitals were resurveyed in 2000 to identify changes from the original survey. Surveys were mailed to the ED nurse manager or equivalent. Survey responses were anonymous. RESULTS: Most hospitals reported fewer violent episodes after the implementation of AB508. However, 32% of hospitals reported that 5 or more verbal threats occurred monthly, and 5% reported that 5 or more violent injuries occurred monthly. Overall, hospitals reported improvements in security programs. The most notable increase was in employee training, which rose from 34% to 95.6% of reporting hospitals. However, almost a quarter of hospitals reported not having general violence prevention policies, and many believed that security personnel were inadequate. DISCUSSION: Although results reported here cannot be directly attributed to AB508, the increase in security program components suggests that hospitals are responding positively to reduce violence. The high prevalence of threats and violent events reported indicates a persistent risk of violence against health care workers.  相似文献   
7.
Several procedures have been described for the culture of Clostridium difficile from stool specimens. The goal of this study was to determine the effectiveness of five of these methods for the isolation of C. difficile from feces of patients suspected of having C. difficile-associated illness. A total of 564 stool specimens were cultured by using heat shock, ethanol treatment (ET), and direct plating on Carr-Scarborough cycloserine-cefoxitin-fructose agar (CCFA) with horse blood (C/S medium), BBL CCFA medium, and Remel C. difficile agar. Cytotoxin assays were performed on all specimens. A total of 113 specimens (20%) were positive for C. difficile by one or more methods. The numbers of positive cultures by using heat shock, ET, and direct plating on C/S medium, BBL CCFA medium, and Remel C. difficile agar were 79 (70%), 89 (79%), 91 (81%), 79 (70%), and 52 (46%), respectively. We concluded that ET and direct plating on C/S medium were the most effective procedures for isolating C. difficile from stool specimens and found significant variation in the performance of modified CCFA from different manufacturers.  相似文献   
8.
The retinal ganglion cell layer of five species of reef teleosts was studied from Nissl-stained whole-mounts and the distribution of neural elements determined quantitatively. Iso-density contour maps of neurons in the ganglion cell layer revealed a temporal area centralis (ranging from 3.5 to 8.3 x 10(4) cells/mm2) which often extended into a horizontal streak (ranging from 1.4 to 5.0 x 10(4) cells/mm2) across the retinal meridian. Species possessing a marked horizontal streak were found to inhabit open water and perceive their environment with an uninterrupted view of sand-water horizon. The behavioural significance of these horizontal areas of acute vision is also discussed.  相似文献   
9.
Non-digestible oligosaccharides — potential anticancer agents?   总被引:1,自引:0,他引:1  
  相似文献   
10.
The loss of myelin, a major element involved in the saltatory conduction of the electrical impulse of the nervous system, is a major target of current research. Serious long-term disabilities are observed in patients with demyelinating disease of the central nervous system, such as multiple sclerosis. New therapeutic strategies aimed at overcoming myelin damage and axonal loss focus on the repair potential of myelin-forming cells. This review examines the use of peripheral myelin-forming cells, the Schwann cells, to promote myelin repair.  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