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   1530篇
  免费   78篇
  国内免费   10篇
耳鼻咽喉   11篇
儿科学   74篇
妇产科学   13篇
基础医学   108篇
口腔科学   35篇
临床医学   177篇
内科学   517篇
皮肤病学   21篇
神经病学   26篇
特种医学   249篇
外科学   133篇
综合类   61篇
预防医学   78篇
眼科学   20篇
药学   50篇
中国医学   9篇
肿瘤学   36篇
  2022年   2篇
  2021年   6篇
  2020年   8篇
  2019年   12篇
  2018年   26篇
  2017年   16篇
  2016年   8篇
  2015年   24篇
  2014年   55篇
  2013年   90篇
  2012年   62篇
  2011年   57篇
  2010年   51篇
  2009年   75篇
  2008年   50篇
  2007年   75篇
  2006年   53篇
  2005年   51篇
  2004年   49篇
  2003年   32篇
  2002年   39篇
  2001年   27篇
  2000年   29篇
  1999年   23篇
  1998年   93篇
  1997年   60篇
  1996年   66篇
  1995年   44篇
  1994年   52篇
  1993年   45篇
  1992年   20篇
  1991年   11篇
  1990年   20篇
  1989年   43篇
  1988年   34篇
  1987年   28篇
  1986年   22篇
  1985年   18篇
  1984年   17篇
  1983年   18篇
  1982年   14篇
  1981年   21篇
  1980年   13篇
  1979年   8篇
  1978年   9篇
  1977年   17篇
  1976年   8篇
  1975年   11篇
  1973年   2篇
  1971年   2篇
排序方式: 共有1618条查询结果,搜索用时 156 毫秒
101.
102.
The acute aortic syndrome (AAS) is described. Its pathophysiology is discussed for each of the three entities (penetrating aortic ulcer, intramural hematoma and aortic dissection). The natural history of these three pathologies is reviewed. Diagnostic features and investigation imaging techniques are summarized. The technique of stentgraft-placement is described in detail. The authors report their clinical experience with 127 patients, presenting acute type B aortic dissection or its variants, and treated with an endovascular stent-graft-device. These results are in part compared with a group of control patients with acute type B dissection, submitted to medical non-invasive therapy.  相似文献   
103.
目的 对比分析下肢骨肉瘤的X线与MRI表现,探讨MRI对骨肉瘤的诊断价值。方法 收集经手术或病理穿刺活检证实的下肢骨肉瘤15例,男11例,女4例,均行MRI平扫及增强扫描(4例行CT扫描),并摄有X线平片,对其MRI征象与X线征象作逐一对比。结果 MRI及X线平片对下肢骨肉瘤的诊断准确率均为100%,MRI在显示病变范围、放射状骨针、Codman三角两层结构以及跳跃病灶等方面明显优于X线平片检查。结论 X线平片是诊断骨肉瘤最简便而实用的方法,但MRI可以更好的显示病变的范围,发现早期病变。  相似文献   
104.
神经节细胞瘤是一种神经内分泌肿瘤,其发生与自主神经系统的交感或副交感神经节有关。罕见发生于膀胱、前列腺和子宫。本文作者报道1例发生于儿童头皮的原发性皮肤神经节细胞瘤。对此肿瘤进行了组织学、免疫组化和超微结构研究。该病例可能代表神经嵴细胞向鳃弓发育过程中的一种异常迁移。此外,研究结果还强调在胚胎发育过程中神经嵴和鳃弓/裂之间有复杂的相互作用。  相似文献   
105.
106.
一例AML中一种新的TCRδ基因重排及其分析方法   总被引:5,自引:0,他引:5  
李扬秋 Wichm.  A 《癌症》1996,15(2):90-93
T细胞抗原受体(TCR)功能的表达有赖于该基因在正常T淋巴细胞发育过程中的重排。近年来,已发现一些肿瘤及白血病中出现该基因的异常重排。我们采用聚合链反应(PCR)、“磁珠”固相纯化方法和PCR产物直接测序等方法,从一例AML中发现了一种在白血病中未报道过的TCRδ基因重排,该重排是一种新报道的Dδ区DδX片段的重排,为DδXDδDδJδ不完全重排。在研究白血病TCR基因重排中,采用本文所报道的方法  相似文献   
107.
Essential fatty acids are claimed to have positive effects in atopic diseases. In a double blind, placebo controlled, parallel group study 58 out of 60 children, with atopic dermatitis and the need for regular treatment with topical skin steroids, completed a 16 weeks' treatment period with either Epogam evening primrose oil or placebo capsules. Twenty two of these subjects also had asthma. The parents used diaries to record symptom scores and concomitant medication. Peak expiratory flow was measured and disease activity was monitored by the clinician every four weeks. The plasma concentrations of essential fatty acids increased significantly in the group treated with Epogam capsules. The study demonstrated significant improvements of the eczema symptoms but no significant difference was found between the placebo and the Epogam groups. No therapeutic effect was shown on asthma symptoms or fidget.  相似文献   
108.
A premature infant developed pericardial effusion four days after the insertion of a 25-gauge silastic percutaneous central venous catheter. The effusion contained parenteral nutrition fluid and resolved rapidly after withdrawal of the catheter. Pericardial effusion is a potential complication of percutaneous, as well as surgically placed, central venous catheters.  相似文献   
109.
We present a simple, fast, non-radioactive method for the analysis of the polymorphic short tandem repeat (STR) system in the human phenylalanine hydroxylase gene. Previously, sizing of the STR marker involved radiolabelling of PCR amplified fragments and resolution on denaturing polyacrylamide gels using M13 sequencing ladder as a standard. However, this method consistently gave sizes 2 bp longer than the known sequence. The fluorescent method presented here employs internal lane standards and enables accurate sizing of the fragments. To avoid confusion, we suggest that the true fragment lengths are used as reference values in the future. The analysis of STR alleles is valuable for population genetic studies and for targeted mutation screening in phenylketonuria (PKU). It can replace RFLP-based haplotype analysis for carrier detection, and we report its use for prenatal diagnosis in a Northern Irish family with PKU. The analysis of 250 Northern Irish chromosomes, including 128 PKU alleles, showed no significant difference between normal and PKU alleles, with fragment lengths of 238 and 242 bp most common in both groups.  相似文献   
110.
Molecular analysis of PKU in Ireland   总被引:1,自引:0,他引:1  
Classical phenylketonuria (PKU: McKusick No. 261600) is caused by mutations occurring at the phenylalanine hydroxylase (PAH) locus on chromosome 12 and has a prevalence in Ireland of 1 in 4500. We examined 304 independent alleles from 350 patients for the presence of six mutations and have characterized VNTR alleles within the minisatellite region 3' to the PAH gene in patients carrying the most prevalent mutation. R408W was the most common mutation found, with a relative frequency of 42%. All other mutations had relative frequencies of <10%. VNTR analysis showed that the R408W mutation is associated with the VNTR-8 allele in the Irish population, indicating that R408W is associated with RFLP haplotype 1. This differs from that reported from eastern Europe where R408W is associated with RFLP haplotype 2/VNTR-3; an observation which has led several groups to propose a Balto-Slavic origin for this mutation. These results support the hypothesis of a second, independent founding event for the R408W mutation on an RFLP haplotype 1 VNTR-8 chromsome background in the Irish/Celtic population.  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