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   8020篇
  免费   444篇
  国内免费   203篇
耳鼻咽喉   102篇
儿科学   349篇
妇产科学   233篇
基础医学   414篇
口腔科学   80篇
临床医学   1269篇
内科学   2025篇
皮肤病学   55篇
神经病学   198篇
特种医学   240篇
外科学   1387篇
综合类   1059篇
预防医学   216篇
眼科学   80篇
药学   498篇
  4篇
中国医学   381篇
肿瘤学   77篇
  2023年   161篇
  2022年   234篇
  2021年   350篇
  2020年   333篇
  2019年   298篇
  2018年   326篇
  2017年   226篇
  2016年   244篇
  2015年   244篇
  2014年   562篇
  2013年   512篇
  2012年   444篇
  2011年   508篇
  2010年   367篇
  2009年   400篇
  2008年   353篇
  2007年   382篇
  2006年   332篇
  2005年   289篇
  2004年   210篇
  2003年   189篇
  2002年   183篇
  2001年   163篇
  2000年   157篇
  1999年   124篇
  1998年   101篇
  1997年   89篇
  1996年   89篇
  1995年   97篇
  1994年   83篇
  1993年   71篇
  1992年   65篇
  1991年   55篇
  1990年   38篇
  1989年   32篇
  1988年   36篇
  1987年   35篇
  1986年   21篇
  1985年   31篇
  1984年   40篇
  1983年   20篇
  1982年   28篇
  1981年   28篇
  1980年   19篇
  1979年   18篇
  1978年   13篇
  1977年   16篇
  1976年   17篇
  1975年   6篇
  1973年   6篇
排序方式: 共有8667条查询结果,搜索用时 15 毫秒
1.
BackgroundSelection of the transcatheter heart valve size for a mitral valve-in-valve procedure is based on the type and manufacturer’s labelled size. However, accurate information of surgical heart valve (SHV) size may not be available in the patient’s medical record. The purpose of this study is to establish reference data for computed tomography (CT) dimensions of commonly used mitral SHV in order to determine the manufacturer’s labelled size from a cardiac CT data set.MethodsCT datasets of 105 patients with surgical mitral bioprosthesis and available manufacturer labeled datasets were included in the analysis. CT derived valve dimensions were assessed by two observers using multiplanar reformats aligned with the basal sewing ring. A circular region of interest was used in a standardized fashion to minimize influence of image acquisition and reconstruction parameters. Interobserver variability was assessed by Bland-Altman analysis.ResultsThe CT-derived dimensions were stratified by valve size and type, and SHV properties were demonstrated for 5 common valve types. Variability of measurements was small and inter-observer limits of agreement were narrow. Stratified by SHV type, no overlap was noted for CT-derived dimensions among different SHV sizes . A reference table of CT characteristics of surgical mitral bioprosthesis types was created.ConclusionThe study provides reference CT data for determining the manufacturers’ labeled SHV size across a range of commonly used mitral SHVs. The findings will be important to help identify types of surgical mitral bioprosthesis utilizing CT characteristics for patients without SHV size documentation.  相似文献   
2.
3.
4.
5.
6.
7.
ObjectiveThis study aimed to clarify the effectiveness of cervical cerclage in preventing recurrent preterm births.Materials and methodsA retrospective study was conducted using the perinatal registration database of the Japan Society of Obstetrics and Gynecology for the Perinatal Center from 2014 to 2016. The efficacies of history-indicated, ultrasound-indicated, and physical examination-indicated cerclage as preventive treatments for women with a history of preterm birth were evaluated by comparing cerclage and non-cerclage cases. Fisher's exact test was performed to evaluate any significant differences in patient backgrounds. Prior to the evaluation, propensity score matching was performed for history-indicated and ultrasound-indicated cerclage patients.ResultsFor this study, 6060 multiparous women with a history of preterm birth were reviewed. After excluding 17 patients with unknown indications for cervical cerclage, 6043 patients were included in the study. History-indicated and ultrasound-indicated cerclage did not reduce the risk of preterm birth in subsequent pregnancies for any of the pregnancy periods (p = 0.413, p = 1.000). In contrast, physical examination-indicated cerclage significantly reduced the risk of subsequent preterm births for all pregnancy periods (p < 0.001).ConclusionSubsequent preterm births were effectively prevented only in physical examination-indicated cerclage cases. For history- or ultrasound-indicated cerclage, statistically significant differences in subsequent preterm births were not evident.  相似文献   
8.
9.
10.
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