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   695篇
  免费   54篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   61篇
妇产科学   5篇
基础医学   89篇
口腔科学   4篇
临床医学   68篇
内科学   134篇
皮肤病学   8篇
神经病学   67篇
特种医学   19篇
外科学   102篇
综合类   9篇
预防医学   91篇
眼科学   19篇
药学   53篇
中国医学   1篇
肿瘤学   16篇
  2022年   3篇
  2021年   31篇
  2020年   9篇
  2019年   12篇
  2018年   14篇
  2017年   13篇
  2016年   7篇
  2015年   15篇
  2014年   17篇
  2013年   23篇
  2012年   37篇
  2011年   41篇
  2010年   22篇
  2009年   18篇
  2008年   27篇
  2007年   30篇
  2006年   41篇
  2005年   32篇
  2004年   33篇
  2003年   31篇
  2002年   22篇
  2001年   22篇
  2000年   29篇
  1999年   21篇
  1998年   17篇
  1997年   17篇
  1996年   18篇
  1995年   9篇
  1994年   11篇
  1993年   6篇
  1992年   14篇
  1991年   5篇
  1990年   9篇
  1989年   12篇
  1988年   9篇
  1987年   7篇
  1986年   6篇
  1985年   8篇
  1982年   2篇
  1981年   4篇
  1980年   4篇
  1978年   3篇
  1977年   5篇
  1976年   4篇
  1975年   7篇
  1973年   5篇
  1972年   3篇
  1971年   4篇
  1967年   3篇
  1966年   2篇
排序方式: 共有750条查询结果,搜索用时 15 毫秒
1.
2.
This paper describes a study to capture the key roles and activities of nephrology nurses across different countries in Europe. The concept of the study and the need to clarify the activities of the nephrology nurse arose as part of a larger study to develop the European Practice Database (EPD) (1). The Research Board (EDTNA/ERCA) needed to identify key questions that would detect significant differences in the role and responsibilities of nephrology nurses in different countries and monitor the evolution over time of nephrology nursing practice in Europe. It was therefore appropriate to devise a separate small study to generate evidence based questions for the EPD and confirm the reliability and usefulness of the information captured.  相似文献   
3.
Advanced age has been associated with a wide range of defects in both the innate and adaptive immune systems including diminished specific antibody responses that increase the risk of invasive pneumococcal disease (IPD) and limit the effectiveness of vaccines. However, the elderly are a heterogeneous group and measures of overall frailty may be a better indicator of disease susceptibility (or vaccine response) than chronological age alone.  相似文献   
4.
Medication strategies in childhood aggression: a review.   总被引:1,自引:0,他引:1  
OBJECTIVE: To review studies of psychopharmacological management of aggression in common childhood psychiatric disorders. METHOD: Using OVID software, we searched Medline for studies that were undertaken in the last 30 years. Controlled and uncontrolled data are summarized for each condition. RESULTS: A paucity of evidence-based information currently exists. Even so, specific indications from the existing literature can be suggested for several classes of psychotropics, particularly in conduct disorder (CD), attention-deficit hyperactivity disorder (ADHD), mood disorders, and other conditions. CONCLUSIONS: Clinicians can use findings from reviewed controlled and, where necessary, uncontrolled studies to inform pharmacologic practice. This review offers suggestions for future research directions that will aid clinical practice.  相似文献   
5.
6.
BACKGROUND. The incidence of infection increases with the prolonged use of central vascular catheters, but it is unclear whether changing catheters every three days, as some recommend, will reduce the rate of infection, It is also unclear whether it is safer to change a catheter over a guide wire or insert it at a new site. METHODS. We conducted a controlled trial in adult patients in intensive care units who required central venous or pulmonary-artery catheters for more than three days. Patients were assigned randomly to undergo one of four methods of catheter exchange: replacement every three days either by insertion at a new site (group 1) or by exchange over a guide wire (group 2), or replacement when clinically indicated either by insertion at a new site (group 3) or by exchange over a guide wire (group 4). RESULTS. Of the 160 patients, 5 percent had catheter-related bloodstream infections, 16 percent had catheters that became colonized, and 9 percent had major mechanical complications. The incidence rates (per 1000 days of catheter use) of bloodstream infection were 3 in group 1, 6 in group 2, 2 in group 3, and 3 in group 4; the incidence rates of mechanical complications were 14, 4, 8, and 3, respectively. Patients randomly assigned to guide-wire-assisted exchange were more likely to have bloodstream infection after the first three days of catheterization (6 percent vs. 0, P = 0.06). Insertions at new sites were associated with more mechanical complications (5 percent vs. 1 percent, P = 0.005). CONCLUSIONS. Routine replacement of central vascular catheters every three days does not prevent infection. Exchanging catheters with the use of a guide wire increases the risk of bloodstream infection, but replacement involving insertion of catheters at new sites increases the risk of mechanical complications.  相似文献   
7.
The validity of a simple clinical classification of acute ischaemic stroke   总被引:6,自引:0,他引:6  
The aim of the study reported here was to test the validity of a simple clinical classification of acute ischaemic stroke (Oxfordshire Community Stroke Project, OCSP) in predicting the site and size of cerebral infarction on computed tomography (CT). Consecutive patients admitted to hospital with acute ischaemic stroke were prospectively identified and classified into one of four clinical syndromes according to the OCSP classification, blind to the result of CT. The CT brain scans were classified blind to the clinical features into those demonstrating: small, medium or large cortical infarcts; small or large subcortical infarcts in the anterior circulation territory; and posterior cerebral circulation territory infarcts. A total of 108 patients were included. A recent infarct was seen. on the CT scan in 91 patients (84%), and the clinical classification correctly predicted the site and size of the cerebral infarct in 80 of these (88%; 95% confidence interval 77–92%). The positive predictive value was best for large cortical infarcts (0.94) and worst for small subcortical infarcts (0.63). The OCSP clinical classification is a reasonably valid way of predicting the site and size of cerebral infarction on CT and can, therefore, be used very early after stroke onset before the infarct appears on the scan.  相似文献   
8.
AIMS--To assess histologically the amount of iron deposited in liver biopsy specimens from HIV positive patients; and to perform estimations of liver iron on tissue from patients with an increase in parenchymal stainable iron. To correlate the amount of blood transfused and the degree of iron overload. METHODS--Liver biopsy specimens (n = 120) from 109 HIV positive patients, 74 of whom had AIDS, were examined retrospectively and the amount of iron, as visualised with Perls's stain, was graded. Fibrosis was assessed using connective tissue stains. Estimations of liver iron were performed on tissue retrieved from paraffin wax blocks in cases with histological grade 3 or 4 iron overload. The amount of blood transfused before liver biopsy was determined from the notes for each patient. RESULTS--Fifteen of the 120 liver biopsy specimens had significantly increased amounts of iron in their hepatocytes, as assessed histologically, and this was confirmed in seven cases by measurement of liver iron. There was a close correlation between the amount of blood transfused and the degree of iron overload. In the initial biopsy specimens only one case showed portal tract expansion. Three of the five patients who had repeat biopsies, however, showed progressive fibrosis. CONCLUSION--Multiply transfused HIV positive patients may develop clinically important iron overload and are at risk of developing progressive fibrosis. Superimposed liver disease, especially viral hepatitis, in these high risk patients may exacerbate the effects of the iron overload.  相似文献   
9.
1. The membrane resistance of isolated salivary glands was found to decrease in response to 5-HT. The change in resistance was calcium-dependent. 2. The resistance change of the apical membrane was found to be much greater than the change in resistance of the basal membrane. 3. Potential responses under current-clamped conditions showed that one part of the biphasic response to 5-HT (attributed to an increase in chloride permeability) could be reversed and the other part (attributed to an increase in a potassium pump) could not. 4. These observations have been incorporated into a model which, on evaluation, predicts all of the observed potential changes during the action of 5-HT. It suggests that the potential responses reflect changes in the internal chloride concentration produced by the calcium-dependent increases in chloride permeability.  相似文献   
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