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   4305555篇
  免费   373500篇
  国内免费   15765篇
耳鼻咽喉   62540篇
儿科学   134618篇
妇产科学   112488篇
基础医学   654407篇
口腔科学   119477篇
临床医学   397059篇
内科学   782310篇
皮肤病学   107167篇
神经病学   372213篇
特种医学   172807篇
外国民族医学   912篇
外科学   666723篇
综合类   126126篇
现状与发展   91篇
一般理论   2609篇
预防医学   360230篇
眼科学   101939篇
药学   302237篇
  19篇
中国医学   11360篇
肿瘤学   207488篇
  2021年   56534篇
  2020年   37814篇
  2019年   59290篇
  2018年   76320篇
  2017年   58626篇
  2016年   65277篇
  2015年   78432篇
  2014年   115855篇
  2013年   181051篇
  2012年   120377篇
  2011年   123556篇
  2010年   127286篇
  2009年   131660篇
  2008年   110709篇
  2007年   116579篇
  2006年   126861篇
  2005年   121187篇
  2004年   121574篇
  2003年   112043篇
  2002年   102574篇
  2001年   155565篇
  2000年   151342篇
  1999年   140507篇
  1998年   72653篇
  1997年   68906篇
  1996年   66468篇
  1995年   62267篇
  1994年   56052篇
  1993年   51933篇
  1992年   103445篇
  1991年   99267篇
  1990年   94198篇
  1989年   91816篇
  1988年   85319篇
  1987年   83830篇
  1986年   79530篇
  1985年   77918篇
  1984年   65738篇
  1983年   58520篇
  1982年   47758篇
  1981年   44475篇
  1980年   41754篇
  1979年   57513篇
  1978年   46730篇
  1977年   41199篇
  1976年   38307篇
  1975年   37552篇
  1974年   42217篇
  1973年   40382篇
  1972年   37962篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
991.
992.
993.
994.
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   
995.
996.
997.
998.
999.
1000.
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   
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