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   711840篇
  免费   50271篇
  国内免费   1329篇
耳鼻咽喉   9285篇
儿科学   23403篇
妇产科学   17670篇
基础医学   111202篇
口腔科学   20117篇
临床医学   64139篇
内科学   136171篇
皮肤病学   16244篇
神经病学   50173篇
特种医学   25902篇
外国民族医学   76篇
外科学   105984篇
综合类   14835篇
现状与发展   2篇
一般理论   160篇
预防医学   51576篇
眼科学   16388篇
药学   54361篇
  3篇
中国医学   2368篇
肿瘤学   43381篇
  2021年   5563篇
  2018年   7994篇
  2017年   6209篇
  2016年   6943篇
  2015年   7681篇
  2014年   10455篇
  2013年   15590篇
  2012年   20823篇
  2011年   21864篇
  2010年   12929篇
  2009年   12100篇
  2008年   20310篇
  2007年   21887篇
  2006年   22239篇
  2005年   20819篇
  2004年   20324篇
  2003年   19272篇
  2002年   18808篇
  2001年   36583篇
  2000年   37193篇
  1999年   30608篇
  1998年   7957篇
  1997年   6731篇
  1996年   7044篇
  1995年   6676篇
  1994年   6145篇
  1993年   5633篇
  1992年   23114篇
  1991年   23083篇
  1990年   22439篇
  1989年   22257篇
  1988年   20174篇
  1987年   19556篇
  1986年   18584篇
  1985年   17410篇
  1984年   12767篇
  1983年   10814篇
  1982年   5951篇
  1979年   11592篇
  1978年   8175篇
  1977年   6870篇
  1976年   6614篇
  1975年   7310篇
  1974年   8543篇
  1973年   8189篇
  1972年   7718篇
  1971年   7171篇
  1970年   6918篇
  1969年   6351篇
  1968年   5829篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.

Background

Intramedullary nailing is considered a “gold standard” for treatment of tibial shaft fractures. However, some types of fractures are typically considered as “difficult for nailing”. This group includes the periarticular fractures, fractures of both bones at the same level, comminuted and segmental fractures of the tibia. Fixator-assisted nailing (FAN) is an effective method treatment of these types of fractures. The main requirements for the ideal reduction device are an ease of its installation and an ability of multiplanar fracture reduction. Fixator-assisted nailing (FAN) with the use of two perpendicular to each other monolateral tubular frames perfectly meets these requirements. In this study we present this new surgical technique and the analysis of first 30 cases.

Methods

A prospective analysis was conducted for 30 patients with “difficult for nailing” tibial fractures treated with fixator-assisted nailing in our institution between September 1st, 2017, and March 1st, 2018. The duration of surgery and its different stages, the time of fluoroscopy, difficulties encountered during surgery, were analyzed. Clinical and radiological methods were used to evaluated reduction quality.

Results

In all 30 cases the acceptable reduction was achieved. The mean duration of the surgical procedure was 73.7?±?3?min. The mean duration of fluoroscopy 85.9?±?4.8?s. In 7 cases we faced with technical difficulties, which were successfully addressed.

Conclusion

The described technique of FAN is an effective method for the treatment of “difficult for nailing” tibial fractures. Future multi-centered studies with a larger number of patients are needed to validate our results.  相似文献   
122.
123.
124.
125.
126.
Abstract

This study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos.  相似文献   
127.
128.
129.
Pharmaceutical Chemistry Journal - N-Substituted 4-aryl-2-hydroxy-4-oxobut-2-enoic acid hydrazides and their complexes with Ni(II), Mn(II), Co(II), Cu(II), and Zn(II) were prepared. Their...  相似文献   
130.
Congenital heart disease is a rare but important finding in adults who experience sudden death. Examination of the congenitally malformed heart has historically been considered esoteric and best left to those with expertise. The Cardiac Risk in the Young cardiovascular pathology laboratory based at St George's University of London has now received over 6,000 cases. Of these, 21 congenitally malformed hearts were retained for research and educational purposes. Hearts were assessed using sequential segmental analysis, and causes of death were adjudicated based on thorough macroscopic examination and histology. Congenital malformations that were encountered included atrial septal defects, ventricular septal defects, tetralogy of Fallot, and transposition of the great arteries in both its regular and congenitally corrected variants. Findings also included hearts with mirror-imaged and isomeric atrial appendages. Direct causes of death included myocardial fibrosis, pulmonary hypertension, and hemorrhage. A small but notable proportion did not reveal a substrate for arrhythmia, raising the question of whether the terminal event was due to the congenital heart disease itself, or an underlying channelopathy. Here, we demonstrate the value of simple sequential segmental analysis in describing and categorizing the cases, with the concept of the “morphological method” serving to identify the distinguishing features of the cardiac components. Clin. Anat. 33:394–404, 2020. © 2019 Wiley Periodicals, Inc.  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