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   61461篇
  免费   6130篇
  国内免费   2496篇
耳鼻咽喉   128篇
儿科学   553篇
妇产科学   224篇
基础医学   2476篇
口腔科学   385篇
临床医学   5251篇
内科学   6952篇
皮肤病学   1045篇
神经病学   2041篇
特种医学   613篇
外国民族医学   7篇
外科学   1756篇
综合类   7958篇
现状与发展   5篇
一般理论   3篇
预防医学   3743篇
眼科学   640篇
药学   29634篇
  29篇
中国医学   2937篇
肿瘤学   3707篇
  2024年   230篇
  2023年   1026篇
  2022年   1595篇
  2021年   2203篇
  2020年   2264篇
  2019年   2257篇
  2018年   2312篇
  2017年   2535篇
  2016年   2355篇
  2015年   2360篇
  2014年   4013篇
  2013年   6751篇
  2012年   4109篇
  2011年   4198篇
  2010年   3376篇
  2009年   2997篇
  2008年   2809篇
  2007年   2845篇
  2006年   2572篇
  2005年   2311篇
  2004年   1964篇
  2003年   1802篇
  2002年   1372篇
  2001年   1330篇
  2000年   1031篇
  1999年   870篇
  1998年   775篇
  1997年   723篇
  1996年   591篇
  1995年   553篇
  1994年   472篇
  1993年   398篇
  1992年   453篇
  1991年   377篇
  1990年   301篇
  1989年   242篇
  1988年   245篇
  1987年   236篇
  1986年   182篇
  1985年   195篇
  1984年   160篇
  1983年   122篇
  1982年   105篇
  1981年   85篇
  1980年   56篇
  1979年   57篇
  1978年   67篇
  1977年   46篇
  1976年   47篇
  1975年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
A 38-year-old man developed parkinsonism that progressed to Hoehn and Yahr stage 5 within 4 years of onset. Response to ropinirole deteriorated, levodopa was not tolerated, and subthalamic nucleus stimulation has provided only partial relief of symptoms. He reported heavy use of Ecstasy through most of his twenties and thirties. His neurological problems may be unrelated to his drug use, but it is also possible they represent an idiosyncratic reaction.  相似文献   
52.
ABSTRACT. Nine severely mentally retarded patients with severe epilepsy who were living in an institution were studied during a three-year period by a multi-disciplinary team. A seizure rate serum level chart was made for each patient. It served as the basis for monthly discussions in the team about medication changes. Drug plasma concentrations were monitored monthly. Statistical comparisons between seizure frequency on different drug regimens were made by χ2 test. Withdrawal of all medication was possible in one case and reduction to monotherapy in two cases. In the remainder of the patients a combination of two or three anticonvulsants gave the best clinical effect. We thus found polypharmacotherapy necessary for some severely retarded patients with epilepsy. Our multidisciplinary approach and chart monitoring system has many advantages and is valuable for the medical care and drug treatment of this patient category.  相似文献   
53.
原发性高血压患者425例(男252,女173;年龄60±s12a)采用美托洛尔100mg,po,每晨1次,4wk为一个疗程。总有效率82.4%,治疗2wk后血压继续下降,心率并不继续减慢。不良反应主要为心率减慢后的症状及神经系症状,停药率6.4%。60a以上的患者总有效率及停药率与中、青年患者无明显区别。故美托洛尔同样适用于老年人。  相似文献   
54.
55.
本文建立了在常温常速离心条件下进行样品预处理的人血浆三尖杉酯碱高效液相色谱荧光测定法。本法批内CV%为3.08~3.47%,批间CV%为4.36~5.28%,回收率范围为93.6~95%,标准曲线在12.5~500ng/ml范围内线性良好(r=0.998)。方法简单、快速、准确,适于临床应用。  相似文献   
56.
Poor nutritional status and inadequate dietary intake in intravenous drug misusers (IVDMs) is a well-recognized problem among those involved in their care. However, there are very few published studies to substantiate these observations. This paper provides a review of the current literature and outlines the aims of dietary advice for IVDMs.  相似文献   
57.
Abstract The purpose of this study was to determine the clinical response to local delivery of tetracycline in relation to clinical and microbiological conditions of the other teeth. 4 deep pockets were monitored in 19 subjects with multiple deep periodontal lesions and high counts of P. gingivalis. In 9 patients (XT) only 2 of the selected lesions were treated by placement of tetracycline fibers (Actisite®). while the rest of the dentition was left untreated. In the other 10 patients, all teeth were supragingivally scaled and then treated by application of polymeric tetracycline HCl containing fibers, the whole dentition was subject to full mouth scaling and root planing, and the patients rinsed with 0.2% chlorhexidine (FT). A significant reduction in mean PPD was observed in all treated sites after two months. This reduction was maintained over the following 4 months. The magnitude of the effect was significantly greater in the FT group (1.74 mm) than in the LT group (0.88 mm). The mean attachment level changes were similar after 2 months in locally and fully treated subjects. A tendency of relapse was noted for treated sites in LT patients from month 2 to 6. A level of statistical significance was not reached for this effect. Data from measurements recorded at 6 sites around all teeth in the full mouth treated patients were analyzed using multiple linear regression. This analysis showed local changes in PPD and AL were significantly and strongly correlated with the baseline value of the respective parameter at the same site. In addition, more pocket depth reduction was noted if a site was not bleeding on probing at 6 months, if the location of a site was not approximal and if the tooth was not a second molar. Sites located on second molars showed also less AL gain than sites located on other teeth. Smokers showed significantly less reduction in PPD and significantly less AL gain. Furthermore, if subjects had a high % of pockets deeper than 4 mm at baseline they showed significantly less attachment gain.  相似文献   
58.
Objective : To measure the geometric resistance to blood flow in human colorectal carcinoma. Although tumor blood flow is of central importance in both the detection and the treatment of cancer, the determinants of blood flow through the neoplastic circulation are poorly understood. Methods : Human colorectal carcinomas (tissue weight = 272 g ± 43 g (SD), n = 6) were perfused ex vivo with a buffered physiological salt solution of known viscosity at flow rates ranging from 2.5 to 40 ml/min and perfusion pressures from 8 to 100 mm Hg. The geometric resistance was determined from the slope of the pressure-flow curve. For examination of the principal determinant of geometric resistance, the vascular architecture, one of the tumors was perfused with Batson's No. 17 polymer and macerated in KOH to produce a positive vascular cast that was used for measurement of vascular branching patterns and dimensions. Results : The pressure-flow relationship was linear at perfusion pressures above 40 mm Hg, and the geometric resistance, z0, was constant at approximately 6.5 ± 109g/cm3. Below 40 mm Hg, z0 increased rapidly. The architecture of the arteriolar and capillary networks of human colorectal carcinoma is similar to those of experimental rodent tumors. Capillaries in planar and nonplanar mesh-works had mean segment diameters of 11 ± 2 and 9.6 ± 2 μm, lengths of 46 ± 24 and 107 ± 40 μm, and intercapillary distances of 46 ± 13 and 74 ± 24 μm, respectively. Conclusions : The geometric flow resistance in neoplastic tissue is 1–2 orders of magnitude higher than that observed in normal tissues. A decrease in functional vascular cross-sectional area may explain the additional increase in resistance at small perfusion pressures. The observed flow resistance may be due to the specialized arteriolar and capillary network architecture, pressures exerted by proliferating cancer cells, and/or coupling between vascular and extravascular flow. These observations demonstrate that tumor vascularity alone may not be indicative of flow resistance or tumor susceptibility to blood-borne therapeutic agents.  相似文献   
59.
Summary The influence of treatment with ponsinomycin, a new macrolide antibiotic, on the pharmacokinetics of cyclosporin A has been studied in 10 renal transplant patients. The pharmacokinetics of cyclosporin A was investigated at steady state, before and during treatment with ponsinomycin.On average, the blood levels of cyclosporin A were doubled by the macrolide, possibly due to a decrease in elimination or/and to an increase in absorption.Ponsinomycin should be use very carefully in patients treated with cyclosporin A.  相似文献   
60.
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