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   91649篇
  免费   5765篇
  国内免费   1603篇
耳鼻咽喉   484篇
儿科学   2192篇
妇产科学   1487篇
基础医学   4833篇
口腔科学   1394篇
临床医学   13587篇
内科学   23510篇
皮肤病学   588篇
神经病学   3283篇
特种医学   1532篇
外国民族医学   1篇
外科学   11987篇
综合类   11768篇
现状与发展   4篇
一般理论   9篇
预防医学   8242篇
眼科学   317篇
药学   8197篇
  130篇
中国医学   3656篇
肿瘤学   1816篇
  2025年   68篇
  2024年   1387篇
  2023年   2113篇
  2022年   3036篇
  2021年   4223篇
  2020年   4438篇
  2019年   4029篇
  2018年   3722篇
  2017年   3464篇
  2016年   3290篇
  2015年   3216篇
  2014年   6203篇
  2013年   7359篇
  2012年   4726篇
  2011年   5453篇
  2010年   4222篇
  2009年   4258篇
  2008年   4139篇
  2007年   4146篇
  2006年   3576篇
  2005年   3288篇
  2004年   2584篇
  2003年   2188篇
  2002年   1827篇
  2001年   1737篇
  2000年   1287篇
  1999年   1139篇
  1998年   939篇
  1997年   820篇
  1996年   798篇
  1995年   683篇
  1994年   658篇
  1993年   470篇
  1992年   433篇
  1991年   407篇
  1990年   349篇
  1989年   334篇
  1988年   303篇
  1987年   246篇
  1986年   215篇
  1985年   247篇
  1984年   190篇
  1983年   117篇
  1982年   130篇
  1981年   112篇
  1980年   96篇
  1979年   90篇
  1978年   74篇
  1977年   47篇
  1976年   53篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
31.
32.
Summary Treatment with L-threo-3,4-dihydroxyphenylserine (L-threo-dops), a synthetic precursor of norepinephrine, significantly increased upright blood pressure in patients with multiple system atrophy but had no effect on the upright blood pressure of patients with pure autonomic failure. These results suggest that the site of action of L-threo-dops is central and that its pressor effect requires intact peripheral sympathetic neurons.  相似文献   
33.
We describe the clinical and pathological findings of the hemolytic uremic syndrome (HUS) in two children with human immunodeficiency virus (HIV) infection. Both patients presented with microangiopathic hemolytic anemia, thrombocytopenia, and subsequently developed renal failure. The diagnosis of HUS was confirmed by renal histopathology in both patients. None of these children presented with bloody diarrhea, evidence of circulating antibody response to Escherichia coli O157 lipopolysaccharide, or other known risk factors for HUS, except for the presence of HIV infection. Each patient was treated with intravenous plasma infusion and renal replacement therapy. Their clinical course was characterized by non-oliguria and lack of significant hypertension throughout the acute phase of the disease. Despite these favorable clinical parameters, both patients developed end-stage renal failure. The etiology of this atypical HUS characterized by poor renal survival remains unknown and the role of HIV infection in its pathogenesis, although possible, is unclear. Received March 5, 1996; received in revised form and accepted October 15, 1996  相似文献   
34.
The quality of medical education during internship is a cause for concern. This paper describes a structured educational programme for interns that was based around learning modules, clinical attachments and bedside teaching. The programme was incorporated into the term rotation of interns within an Area Health Service, and evaluated. Learning modules were timetabled by a Programme Coordinator and interns were reminded to attend. Clinical attachments were organized by the interns from a list of willing supervisors. Attendance at timetabled learning modules averaged 67%, which was greater than the 27% attendance at clinical attachments. Both sessions received high ratings for quality and clinical relevance. This structured education programme was based upon adult learning methods and was both feasible and well received by interns. Intern training programmes need to be programmed into the working week to ensure attendance, and modified following evaluation by interns. Such programmes should be considered by all hospitals to which interns are allocated.  相似文献   
35.
Success of meniscal repair with early or immediate motion depends on the ability of the suture fixation to withstand the loads applied. Vertical and horizontal mattress suture techniques were tested using 2-0 Ethibond, and 0-PDS and 1-PDS sutures (Ethicon, Somerville, NJ). Mulberry knot technique was tested with 0-PDS and 1-PDS sutures. Twenty menisci (60 sutures) were tested for each suture material. Sutures were placed 3 to 4 mm from the peripheral edge of the meniscus with double barreled cannulas for vertical and horizontal mattress techniques or a spinal needle for the mulberry knot technique, reproducing clinical techniques of meniscal repair. Mechanical testing of suture fixation was performed to failure at a rate of 10 mm/min on a MTS material testing system (MTS Systems Corp. Minneapolis, MN). Suture pullouts were reported as the load displacement to failure from the inner fragment only, because clinical failure would ensue should a suture pull through the inner fragment of a tear. Vertical mattress technique with 1-PDS suture had significantly greater load to failure than any other combination (P < .05). Analysis of variance showed that the vertical mattress technique had statistically superior pullout strength (P < .0001) compared with the horizontal mattress and mulberry knot techniques, which were statistically similar. There were significant differences (P < .0001) between suture types, with 1-PDS proving best compared with 0-PDS, which was stronger than 2-0 Ethibond. Selection of suture material had the greatest impact on vertical mattress load to failure and was not important to the strength of the other techniques.  相似文献   
36.
采用放射免疫法测定60例心血管病患儿的血浆心钠素,结果,在心功能不全,先天性心脏病、心肌炎者,明显高于正常组;心功能不全组明显高于非心功能不全组。非心功能不全的心血管疾患(如:先天性心脏病、心肌炎)之间无显著差异。说明血浆心钠素测定可作为心功能不全判断指标,并可指导治疗。  相似文献   
37.
A case of partially reversible chronic renal failure due tolong-term NSAID use is discussed. An analysis of this and similarcases recently reported indicates many similarities betweenchronic NSAID nephropathy and analgesic nephropathy.  相似文献   
38.
In multiple sclerosis (MS) up-regulation of β-adrenoceptors on peripheral blood mononuclear cells (PBMCs) has been attributed to either autonomic dysfunction, inflammation or a combination of the two. We have compared secondary progressive MS patients with normal subjects (NS) and two models of autonomic dysfunction; pure autonomic failure (PAF) and multiple system atrophy (MSA, Shy-Drager syndrome). There was up-regulation of β-adrenoceptors on PBMCs in MS and PAF patients but not in MSA patients. Only in PAF patients β-adrenoceptor up-regulation was correlated with low plasma levels of noradrenaline (NA) and adrenaline (Ad). In addition to studies in the basal state, measurements also were made after the centrally acting sympatholytic agent clonidine. These were combined with haemodynamic and neurohormonal measurements. After clonidine, there was a fall in blood pressure in NS and MSA patients but not in MS and PAF patients; a rise in growth hormone (GH) in NS and PAF patients but not in MS and MSA patients; and an up-regulation in PBMCs β-adrenoceptors in NS but not in MS, MSA and PAF patients. Up-regulation of β-adrenoceptors on PBMCs in MS could be attributed to autonomic dysfunction but the disparity between MS and PAF patients when considering their plasma levels of NA and Ad argue against. Although the neurohormonal responses to clonidine and the physiological assessment of autonomic function in progressive MS patients, demonstrate central autonomic dysfunction resembling that of the MSA patients, the normal basal β-adrenoceptor densities in the latter, suggests that the up-regulation of these receptors is independent of the central autonomic dysfunction in MS.  相似文献   
39.
18只犬切除右肾,钳夹左肾动脉60分的肾缺血模型,再灌注5小时。将动物随机分成对照组、川芎嗪组及维拉帕米组。观察尿量、菊糖清除率、利钠指数、平均动脉压及心率;再灌注5小时取肾组织作形态学检查。结果显示川芎嗪对肾功能及形态有保护作用,维拉帕米则无此作用,提示在手术中有肾缺血时以川芎嗪作为肾保护药物优于维拉帕米。  相似文献   
40.
The non-sulfhydryl selective angiotensin-converting enzyme inhibitor benazepril (20 mg daily) was compared with hydrochlorothiazide (50 mg daily) in post-infarction (6-24 months) patients with symptomatic (NYHA functional class 2) mild heart failure. No concomitant drug therapy was given. The study had a double-blind cross-over design with 3-month treatment periods. Both drugs were well tolerated, and both caused a similar reduction in systolic blood pressure. Heart rate was higher with the diuretic. Benazepril improved the NYHA functional class in 17 out of 29 (59%) patients, whereas one patient improved with hydrochlorothiazide (P = 0.0004). With regard to global efficacy score, benazepril was also superior. Thus, angiotensin-converting enzyme inhibitors may be superior to diuretics as first-choice therapy in symptomatic mild heart failure.  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