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   5850篇
  免费   645篇
  国内免费   169篇
耳鼻咽喉   58篇
儿科学   239篇
妇产科学   139篇
基础医学   176篇
口腔科学   84篇
临床医学   1255篇
内科学   1294篇
皮肤病学   123篇
神经病学   354篇
特种医学   247篇
外科学   1657篇
综合类   21篇
预防医学   330篇
眼科学   348篇
药学   82篇
肿瘤学   257篇
  2023年   111篇
  2021年   76篇
  2020年   100篇
  2019年   47篇
  2018年   141篇
  2017年   182篇
  2016年   197篇
  2015年   141篇
  2014年   230篇
  2013年   311篇
  2012年   103篇
  2011年   124篇
  2010年   243篇
  2009年   351篇
  2008年   127篇
  2007年   74篇
  2006年   108篇
  2005年   74篇
  2004年   40篇
  2003年   52篇
  2002年   49篇
  2001年   117篇
  2000年   74篇
  1999年   140篇
  1998年   187篇
  1997年   217篇
  1996年   313篇
  1995年   264篇
  1994年   205篇
  1993年   124篇
  1992年   133篇
  1991年   145篇
  1990年   81篇
  1989年   141篇
  1988年   117篇
  1987年   96篇
  1986年   104篇
  1985年   92篇
  1984年   97篇
  1983年   80篇
  1982年   77篇
  1981年   69篇
  1980年   91篇
  1979年   41篇
  1978年   65篇
  1977年   49篇
  1976年   50篇
  1975年   50篇
  1964年   49篇
  1963年   47篇
排序方式: 共有6664条查询结果,搜索用时 0 毫秒
131.
132.
Many patients with single ventricle physiology suffer from atrioventricular valve (AVV) regurgitation which may worsen their cardiac function and cause symptoms. It has been postulated that elimination of the nondominant hypoplastic AVV regurgitation, might improve the clinical status in patients post-Fontan surgery. We describe a case of hypoplastic left heart variant, post Fontan surgery who had severe left AVV regurgitation and underwent percutaneous transcatheter occlusion of the hypoplastic left AVV, using a VSD occluder device. At 3 months post procedure, the patient is improved. Transcatheter closure of a regurgitant hypoplastic AVV in a patient with single ventricle helps to improve the patient's cardiac function and clinical status.  相似文献   
133.
134.
The study was a multicenter double-blind parallel-group comparison of omeprazole, a proton-pump inhibitor, with the H2-receptor antagonist, ranitidine, in 206 patients with duodenal ulcer. There were 145 men and 62 women of mixed racial origin with an average age of 40 years (range 19–76); 63 of them were white, 7 black, 135 coloured and 1 Asian. Each drug was given for four weeks and ulcer healing rate, symptom relief, and adverse events were recorded and compared between treatment groups. Patients received either 20 mg omeprazole once daily in the morning (N=104) or ranitidine 300 mg once daily at night (N =106). Healing rates were significantly higher in the omeprazole group than in the ranitidine group at both two weeks (80% vs 52%,P<0.001) and four weeks (95% vs 85%,P<0.05), using the per protocol approach, and these results were confirmed using the intention to treat approach. Omeprazole-treated patients reported significantly less daytime epigastric pain (P=0.02) and heartburn (P=0.04) after two weeks than ranitidine-treated patients. By four weeks, there were no significant differences in symptom reporting between groups. Both treatments were well tolerated, and there were no serious adverse events.The study materials and funding were provided by Astra Pharmaceuticals International  相似文献   
135.
The effects of single and repeated doses of aspirin on the gastric mucosa of the rat were compared to determine whether the mucosal response alters after repeated aspirin. Aspirin (120 mg/kg) was administered by esophageal intubation either as a single dose or daily for 3, 14, 28 and 56 days. Mucosal damage was present in all treated rats but, on histologic quantitation, there was a highly significant reduction in the numbers of acute erosions in the groups receiving repeated daily aspirin. This apparent adaptation did not persist when aspirin administration was interrupted for 3 days. Repeated aspirin administration was not associated with any reduction in aspirin absorption or excretion, nor was there any significant change in hydrochloric acid or pepsin secretion. The investigation has shown an adaptation to repeated aspirin in the rat which appears to result from an alteration in the gastric mucosa. The precise mechanism of the adaptation remains uncertain.Supported by the National Health and Medical Research Council and the Alfred Hospital.Presented, in part, to the Gastroenterological Society of Australia, May 1971.  相似文献   
136.
137.
138.
139.
140.

Background

Most studies have categorized all antiplatelet drugs into one category. The aim of our study was to evaluate the utility of repeat head computed tomography (RHCT) and outcomes in patients on low-dose aspirin (acetylsalicylic acid; ASA) therapy.

Methods

Patients with traumatic brain injury with intracranial hemorrhage on initial head computed tomography (CT) were prospectively enrolled. Patients on prehospital low-dose (81 mg) aspirin therapy were matched with patients exclusive of antiplatelet and anticoagulation therapy using propensity score matching in a 1:1 ratio for age, Glasgow Coma Scale, head Abbreviated Injury Scale score, Injury Severity Score, and neurological examination. Outcome measures were progression on RHCT and subsequent neurosurgical intervention.

Results

A total of 144 patients who had intracranial hemorrhage on initial CT scan (ASA group: 72; No-ASA group: 72) were enrolled. The mean age was 72.8 ± 11.7 years, 59.7% were male, and median head Abbreviated Injury Scale was 3 (2–3). There was no difference in progression on RHCT (25% in ASA versus 16.6% in no-ASA), change in management as a result of RHCT (1.4% versus 1.4%), RHCT as a result of neurological decline (0 versus 1.4%), discharge Glasgow Coma Scale (15 [14–15] versus 15 [14–15]), and mortality (0 versus 1.4%) between the two groups.

Conclusions

Low-dose aspirin therapy is not associated with progression of initial insult on RHCT or clinical deterioration. Prehospital low-dose aspirin therapy as a sole criterion should not warrant a routine repeat head CT in traumatic brain injury.  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