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   152022篇
  免费   14284篇
  国内免费   10324篇
耳鼻咽喉   1348篇
儿科学   1801篇
妇产科学   1401篇
基础医学   15549篇
口腔科学   2652篇
临床医学   18480篇
内科学   20503篇
皮肤病学   1559篇
神经病学   7421篇
特种医学   6018篇
外国民族医学   66篇
外科学   16589篇
综合类   30256篇
现状与发展   49篇
一般理论   5篇
预防医学   11851篇
眼科学   3496篇
药学   16035篇
  147篇
中国医学   10345篇
肿瘤学   11059篇
  2024年   561篇
  2023年   2210篇
  2022年   5400篇
  2021年   7276篇
  2020年   5673篇
  2019年   4529篇
  2018年   4887篇
  2017年   4691篇
  2016年   4395篇
  2015年   6880篇
  2014年   8484篇
  2013年   8604篇
  2012年   12404篇
  2011年   13560篇
  2010年   9540篇
  2009年   8057篇
  2008年   9392篇
  2007年   8916篇
  2006年   8505篇
  2005年   7597篇
  2004年   5751篇
  2003年   5453篇
  2002年   4602篇
  2001年   3252篇
  2000年   2862篇
  1999年   2381篇
  1998年   1513篇
  1997年   1422篇
  1996年   1133篇
  1995年   1046篇
  1994年   882篇
  1993年   561篇
  1992年   610篇
  1991年   560篇
  1990年   475篇
  1989年   406篇
  1988年   363篇
  1987年   289篇
  1986年   250篇
  1985年   207篇
  1984年   147篇
  1983年   105篇
  1982年   77篇
  1981年   76篇
  1980年   74篇
  1979年   65篇
  1978年   52篇
  1977年   44篇
  1975年   45篇
  1974年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
X Dong  M He  X Song  B Lu  Y Yang  S Zhang  N Zhao  L Zhou  Y Li  X Zhu  R Hu 《Diabetic medicine》2007,24(12):1482-1486
AIMS: Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks. METHODS: A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared. RESULTS: The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks. CONCLUSIONS: These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks.  相似文献   
12.
The purpose of this paper is to describe the design and development of the Clinical Practice Library of Medicine (CPLM). CPLM is an investigational project aimed at providing health care practitioners with critical in-depth information similar to that obtained from a medical reference library or consultant. When used in conjunction with the physician's knowledge, CPLM can provide valuable diagnostic prompting information to assist in rapidly reaching a suitable diagnosis for timely administration of appropriate treatment. This system may also be used to assist paramedical professionals working in remote areas where other expert medical assistance may not be available.  相似文献   
13.
14.
We report a case of extragastrointestinal stromal tumor possibly originating from the prostate. The patient underwent radical prostatectomy because of no metastatic evidence. No recurrence and metastasis have been found during 14 months of follow up. To our knowledge, this may be the third such case published in a report in terms of pathological type.  相似文献   
15.
16.
Magnetic resonance imaging (MRI) of the oropharyngeal region from 20 adult volunteers using four model inhalation devices (varying mouthpiece diameters, airflow resistances) and tidal breathing was carried out. Statistical analysis (convex hull method) selected 12 scans from 80 data sets representing the extremes of all dimensions in the population. Twelve physical mouth-throat models were made by stereolithography using the exact scan data. The aim was to produce models with varying dimensions to span the adult population, and to investigate if oropharyngeal dimensions affected throat retention for different delivery systems. In an in vitro analysis, the models were used to determine the retention effect of the oropharyngeal airspaces when drug aerosols were administered from four inhalation delivery systems: a pressurised metered dose inhaler (pMDI), two different dry powder inhalers (DPIs A and B), and a nebulizer. The aims of this work were to determine the key parameters governing mouth-throat retention and whether retention was dependent on the delivery system used. Characterizing the throat models by measuring 51 different dimensional variables enabled determination of the most influential variables for dose retention for each inhalation delivery system. Throat model retention was found to be dependent on the delivery system (pMDI approximately DPI(A) > DPI(B) > Neb.). The most influential variable was the total throat model volume. Throat models representing high, median, and low oropharyngeal filtration in healthy adults have been identified.  相似文献   
17.
自体表皮细胞培养与异体真皮组合应用研究   总被引:13,自引:0,他引:13  
严重烧伤病人皮肤修复中主要未解决的问题是真皮的替代。动物实验结果表明,异体皮移植后5天,用自体培养表皮细胞膜片覆盖真皮床,14天后复合皮成活率是84.6%±2.4%。组织学检查证实表皮已形成了复层结构,可见基底层、颗粒层和角质层。临床应用中,异体皮移植后10天,去除异体表皮覆盖病人的自体培养表皮,35天后未见排斥征象,异体真皮促进了培养表皮的分层、成熟和完整,组织学检查证实表皮细胞的边缘清楚,已分化形成颗粒层和角质层,真皮多细胞,已血管化,但表皮嵴缺乏。  相似文献   
18.
19.
20.
Patients with moderately severe Parkinson's disease complicated by the adverse effects of chronic levodopa use benefited from the addition of bromocriptine (Parlodel; Sandoz) in doses up to 26 mg daily, which allowed an approximate 30% reduction of levodopa dose. This resulted in a significant decrease in the amount of levodopa side-effects while maintaining or improving the original parkinsonian clinical stage. Increased effectiveness in these patients was not associated with increased dosage beyond 25-30 mg daily. When the doses of bromocriptine were increased slowly, the adverse reactions were minor and usually transient.  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