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   999篇
  免费   74篇
  国内免费   16篇
耳鼻咽喉   16篇
儿科学   49篇
妇产科学   11篇
基础医学   122篇
口腔科学   98篇
临床医学   95篇
内科学   232篇
皮肤病学   35篇
神经病学   112篇
特种医学   131篇
外科学   57篇
综合类   37篇
预防医学   25篇
眼科学   5篇
药学   44篇
中国医学   2篇
肿瘤学   18篇
  2023年   6篇
  2022年   3篇
  2021年   21篇
  2020年   13篇
  2019年   24篇
  2018年   14篇
  2017年   21篇
  2016年   20篇
  2015年   27篇
  2014年   34篇
  2013年   44篇
  2012年   32篇
  2011年   21篇
  2010年   58篇
  2009年   45篇
  2008年   33篇
  2007年   39篇
  2006年   23篇
  2005年   26篇
  2004年   33篇
  2003年   23篇
  2002年   19篇
  2001年   21篇
  2000年   17篇
  1999年   17篇
  1998年   47篇
  1997年   41篇
  1996年   38篇
  1995年   26篇
  1994年   34篇
  1993年   31篇
  1992年   11篇
  1991年   17篇
  1990年   9篇
  1989年   22篇
  1988年   18篇
  1987年   19篇
  1986年   17篇
  1985年   10篇
  1984年   9篇
  1983年   10篇
  1982年   13篇
  1981年   12篇
  1980年   15篇
  1978年   5篇
  1977年   14篇
  1976年   9篇
  1975年   5篇
  1974年   3篇
  1956年   3篇
排序方式: 共有1089条查询结果,搜索用时 15 毫秒
1.
We report the clinical, neurophysiological (comprehending electromyography, nerve conduction velocities, and multimodal evoked potentials), histological study of the nerve and muscle and the effect of vitamin E supplement in a 32-year-old case with chronic vitamin E deficiency subsequent to acquired intestinal malabsorption. An early diagnosis for an early treatment is essential in preventing severe neurological deterioration.  相似文献   
2.
3.
Atraumetic Restorative Treatment (ART) has been adopted around the world to avoid unnecessary extractions, especially in non-industrialized countries The development of specific glass ionomer cements marketed for the ART technique has contributed to the technical success rate. In this study. Ketac-Molara (3M ESPE. Dental Medzn Germany) was used to restore 150 Class I cavities in 118 Brazilian public school children, aged from 7–12 years. At baseline and at subsequent recalls. CPI probes with a ball-end of 0.5 millimeters (mm) were used to assess loss of restorative material, and photographic color transparencies of restorations were made. After six months. 83 patients returned for follow-up examinations, with 71.8% of their restorations designated as acceptable. After three years. 49 patients with 57 ART-restorations were evaluated, with 21.0% of these restorations graded as acceptable Another 29.8% of their restorations had been replaced by more permanent materials. The main objective of the ART technique is tooth retention; this was achieved for 94.7% of the restored teeth in a high caries risk population who returned for recalls.  相似文献   
4.
Gastroesophageal reflux disease (GERD) is the most common disease of the upper gastrointestinal tract. With the introduction of proton pump inhibitors medical treatment of GERD has been significantly improved. However, the development of laparoscopic antireflux surgery resulted in an increasing interest of surgeons in this disease. An interactive meeting was organized in order to develop an agreement between gastoenterologists and surgeons regarding therapeutic decisions and this is the main topic of this paper.  相似文献   
5.
6.
7.
Human beta-defensin 2 (DEFB4, also known as DEFB2 or hBD-2) is a salt-sensitive antimicrobial protein that is expressed in lung epithelia. Previous work has shown that it is encoded in a cluster of beta-defensin genes at 8p23.1, which varies in copy number between 2 and 12 in different individuals. We determined the copy number of this locus in 355 patients with cystic fibrosis (CF), and tested for correlation between beta-defensin cluster genomic copy number and lung disease associated with CF. No significant association was found.  相似文献   
8.
Thanatophoric dwarfism (TD) is a sporadic lethal skeletal dysplasia with micromelic shortening of the limbs, macrocephaly, platyspondyly and reduced thoracic cavity. In the most common subtype (TD1), femurs are curved, while in TD2, straight femurs are associated with cloverleaf skull. Mutations in the fibroblast growth factor receptor 3 (FGFR3) gene were identified in both subtypes. While TD2 was accounted for by a single recurrent mutation in the tyrosine kinase 2 domain, TD1 resulted from either stop codon mutations or missense mutations in the extracellular domain of the gene. Here, we report the identification of FGFR3 mutations in 25/26 TD cases. Two novel missense mutations (Y373C and G370C) were detected in 8/26 and 1/26 TD1 cases respectively. Both mutations created cysteine residues in the juxta extramembrane domain of the receptor. Sixteen cases carried the previously reported R248C (9/26 cases), S249C (2/26 cases) or stop codon FGFR3 mutations (5/26 cases). Our results suggest that TD1 is a genetically homogeneous condition and give additional support to the view that newly created cysteine residues in the extracellular domain of the protein play a key role in the severity of the disease.   相似文献   
9.
Using the natural killer (NK) sensitive K562 cell line, enhanced NK cell cytotoxicity was demonstrable early in the course of acute hepatitis B while normal values were obtained in patients studied during convalescence. No evidence of enhanced NK activity was instead obtained in the course of acute non-A, non-B hepatitis. Serum levels of alpha-interferon, as determined by radioimmunoassay (RIA), were significantly increased in patients with acute hepatitis B showing enhanced NK cell activity but not in those with acute non-A, non-B hepatitis and normal NK cell activity. These results suggest that natural cytotoxicity may play a role early in the course of acute hepatitis type B, before antigen-specific T lymphocytes become fully operative.  相似文献   
10.
We have recently shown using dansyl-L-lysine exclusion studies that the release of human chorionic gonadotrophin (HCG) in conjunction with L- lactate dehydrogenase (LDH) from first trimester villi during organ culture is symptomatic of syncytiotrophoblast degeneration. The purpose of this study was to examine chorionic villi at the ultrastructural level in order to determine events occurring during organ culture. The tissue was sampled after 0, 24, 48 and 120 h in culture and processed for electron microscopy. In addition to confirming the previously recorded syncytial degeneration, the electron micrographs showed clearly the generation of a new syncytiotrophoblast layer. The new layer, derived from differentiating cytotrophoblast cells, was largely formed by 48 h and was maintained for at least 120 h in culture. This study demonstrates a model which provides an opportunity to study the differentiation of cytotrophoblast cells whilst they retain their anatomical relationships within the villous structure.   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