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   4327326篇
  免费   349410篇
  国内免费   14579篇
耳鼻咽喉   60259篇
儿科学   139445篇
妇产科学   114323篇
基础医学   664173篇
口腔科学   117929篇
临床医学   394970篇
内科学   782687篇
皮肤病学   107746篇
神经病学   367488篇
特种医学   169320篇
外国民族医学   753篇
外科学   654623篇
综合类   121119篇
现状与发展   24篇
一般理论   2617篇
预防医学   356208篇
眼科学   100651篇
药学   307274篇
  21篇
中国医学   11933篇
肿瘤学   217752篇
  2021年   56032篇
  2020年   35825篇
  2019年   58835篇
  2018年   74450篇
  2017年   56693篇
  2016年   62816篇
  2015年   75715篇
  2014年   109982篇
  2013年   175560篇
  2012年   124707篇
  2011年   129463篇
  2010年   126015篇
  2009年   127661篇
  2008年   115589篇
  2007年   122877篇
  2006年   131603篇
  2005年   125678篇
  2004年   126984篇
  2003年   117135篇
  2002年   106365篇
  2001年   166947篇
  2000年   162022篇
  1999年   148674篇
  1998年   71666篇
  1997年   67610篇
  1996年   65624篇
  1995年   61045篇
  1994年   54969篇
  1993年   51011篇
  1992年   106572篇
  1991年   101284篇
  1990年   97068篇
  1989年   94612篇
  1988年   86874篇
  1987年   85117篇
  1986年   80000篇
  1985年   78182篇
  1984年   65079篇
  1983年   57776篇
  1982年   46731篇
  1981年   43406篇
  1980年   40607篇
  1979年   54740篇
  1978年   44417篇
  1977年   39538篇
  1976年   36460篇
  1975年   36485篇
  1974年   39369篇
  1973年   37557篇
  1972年   35263篇
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
971.
972.
973.
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.

Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.  相似文献   
974.
975.
976.
977.
978.
979.
Capillary malformation–arteriovenous malformation syndrome (CM‐AVM) is an autosomal dominant disorder caused by RASA1 mutations. The prevalence and phenotypic spectrum are unknown. Evaluation of patients with multiple CMs is challenging because associated AVMs can be life threatening. The objective of this study was to describe the clinical characteristics of children presenting with features of CM‐AVM to an academic pediatric dermatology practice. After institutional review board approval was received, a retrospective chart review was performed of patients presenting between 2009 and 2012 with features of CM‐AVM. We report nine cases. Presenting symptoms ranged from extensive vascular stains and cardiac failure to CMs noted incidentally during routine skin examination. All demonstrated multiple CMs, two had Parkes Weber syndrome, and two had multiple infantile hemangiomas. Seven patients had family histories of multiple CMs; three had family histories of large, atypical CMs. Six had personal or family histories of AVMs. Genetic evaluation was recommended for all and was pursued by six families; four RASA1 mutations were identified, including one de novo. Consultations with neurology, cardiology, and orthopedics were recommended. Most patients (89%) have not required treatment to date. CM‐AVM is an underrecognized condition with a wide clinical spectrum that often presents in childhood. Further evaluation may be indicated in patients with multiple CMs. This study is limited by its small and retrospective nature.  相似文献   
980.
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