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   8464篇
  免费   799篇
  国内免费   31篇
耳鼻咽喉   57篇
儿科学   267篇
妇产科学   146篇
基础医学   1174篇
口腔科学   196篇
临床医学   1029篇
内科学   1706篇
皮肤病学   91篇
神经病学   595篇
特种医学   407篇
外科学   1344篇
综合类   187篇
一般理论   9篇
预防医学   873篇
眼科学   106篇
药学   575篇
肿瘤学   532篇
  2021年   91篇
  2019年   102篇
  2018年   143篇
  2017年   85篇
  2016年   83篇
  2015年   103篇
  2014年   149篇
  2013年   261篇
  2012年   355篇
  2011年   363篇
  2010年   181篇
  2009年   191篇
  2008年   364篇
  2007年   394篇
  2006年   396篇
  2005年   367篇
  2004年   351篇
  2003年   311篇
  2002年   337篇
  2001年   299篇
  2000年   278篇
  1999年   225篇
  1998年   133篇
  1997年   128篇
  1996年   100篇
  1995年   104篇
  1994年   82篇
  1993年   101篇
  1992年   198篇
  1991年   182篇
  1990年   213篇
  1989年   184篇
  1988年   178篇
  1987年   165篇
  1986年   156篇
  1985年   169篇
  1984年   131篇
  1983年   93篇
  1982年   78篇
  1981年   69篇
  1980年   72篇
  1979年   121篇
  1978年   88篇
  1977年   68篇
  1976年   86篇
  1975年   77篇
  1974年   86篇
  1973年   82篇
  1972年   87篇
  1969年   81篇
排序方式: 共有9294条查询结果,搜索用时 0 毫秒
1.
Cancer Chemotherapy and Pharmacology - Addition of solid doxorubicin or solutions to pre-formed liposomes proved to be the optimal method for incorporating the drug into liposomes whilst...  相似文献   
2.
3.
4.
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use.  相似文献   
5.
6.
7.
R C Hunt  D M Bryan  V S Brinkley  T W Whitley  N H Benson 《JAMA》1991,265(15):1982-1984
This study assessed the capabilities of a traditional and an amplified stethoscope used by flight nurses to assess breath sound during air medical transport in an MBB BO-105 helicopter. We developed a normal breath sound model using a prerecorded tape of breath sounds interspersed with segments without breath sounds; the recorder had been placed in the chest wall of a resuscitation training manikin. Flight nurses completed control listening sessions in a quiet environment and experimental sessions during flight using a traditional stethoscope for half of the sessions and an amplified stethoscope for the remaining half. In the quiet environment, flight nurses accurately reported the presence or absence of breath sounds in 110 (92%) of 120 trials. During helicopter flight, none of the flight nurses heard breath sounds during any of the recorded segments with either the traditional stethoscope or the amplified stethoscope. We conclude that flight nurses are unable to hear normal breath sounds using a traditional or amplified stethoscope during flight in a medically configured MBB BO-105 helicopter. Improved stethoscopes, innovative methods of listening, and reduction of aircraft noise are potential solutions to the problems of breath sound assessment during air medical transport.  相似文献   
8.
9.
10.
Most publications citing the effectiveness of renal extracorporeal shock wave lithotripsy have used plain abdominal radiography to assess residual calculi after treatment. We compared radiologist sensitivity and specificity in the detection of calculi on plain abdominal radiographs versus conventional film-screen and digital renal tomograms in extracorporeal shock wave lithotripsy patients. Of the patients 50 were imaged before and within 24 hours after lithotripsy. Six radiologists evaluated the resultant 300 studies for the presence and location of calculi. The mean sensitivity for digital tomograms was 83% for pre-lithotripsy and post-lithotripsy studies, which was significantly higher than for plain abdominal radiography and conventional tomography after lithotripsy. However, there were significantly more false positive stone diagnoses associated with digital tomogram interpretation. Signal detection analysis verified the over-all superiority of digital tomography for post-extracorporeal shock wave lithotripsy imaging. Calculus detection by conventional and digital tomography is superior to detection by plain abdominal radiography. However, because we did not perform delayed imaging, it is not possible to say what impact digital tomography might have on the management of extracorporeal shock wave lithotripsy patients.  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