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   1326593篇
  免费   95862篇
  国内免费   2889篇
耳鼻咽喉   19700篇
儿科学   40135篇
妇产科学   38656篇
基础医学   185704篇
口腔科学   39751篇
临床医学   111911篇
内科学   260034篇
皮肤病学   30169篇
神经病学   105704篇
特种医学   53621篇
外国民族医学   435篇
外科学   207427篇
综合类   30977篇
现状与发展   6篇
一般理论   436篇
预防医学   91432篇
眼科学   31287篇
药学   99833篇
  2篇
中国医学   2948篇
肿瘤学   75176篇
  2018年   11742篇
  2015年   11877篇
  2014年   16695篇
  2013年   25247篇
  2012年   33006篇
  2011年   34866篇
  2010年   20732篇
  2009年   20229篇
  2008年   33584篇
  2007年   36685篇
  2006年   37259篇
  2005年   36011篇
  2004年   35078篇
  2003年   33988篇
  2002年   33498篇
  2001年   63520篇
  2000年   65163篇
  1999年   55021篇
  1998年   13847篇
  1997年   12606篇
  1996年   12102篇
  1995年   12133篇
  1994年   11395篇
  1992年   42702篇
  1991年   41267篇
  1990年   40529篇
  1989年   39523篇
  1988年   36925篇
  1987年   36389篇
  1986年   34871篇
  1985年   33090篇
  1984年   24785篇
  1983年   20981篇
  1982年   12606篇
  1981年   11502篇
  1980年   10706篇
  1979年   23860篇
  1978年   17016篇
  1977年   14761篇
  1976年   13332篇
  1975年   15216篇
  1974年   18039篇
  1973年   17534篇
  1972年   16788篇
  1971年   15694篇
  1970年   14875篇
  1969年   14320篇
  1968年   13438篇
  1967年   11990篇
  1966年   11241篇
排序方式: 共有10000条查询结果,搜索用时 153 毫秒
41.
42.
IntroductionOrgan-based tube current modulation (OBTCM) is designed for anterior dose reduction in Computed Tomography (CT). The purpose was to assess dose reduction capability in chest CT using three organ dose modulation systems at different kVp settings. Furthermore, noise, diagnostic image quality and tumour detection was assessed.MethodsA Lungman phantom was scanned with and without OBTCM at 80–135/140 kVp using three CT scanners; Canon Aquillion Prime, GE Revolution CT and Siemens Somatom Flash. Thermo-luminescent dosimeters were attached to the phantom surface and all scans were repeated five times. Image noise was measured in three ROIs at the level of the carina. Three observers visually scored the images using a fivestep scale. A Wilcoxon Signed-Rank test was used for statistical analysis of differences.ResultsUsing the GE revolution CT scanner, dose reductions between 1.10 mSv (12%) and 1.56 mSv (24%) (p < 0.01) were found in the anterior segment and no differences posteriorly and laterally. Total dose reductions between 0.64 (8%) and 0.91 mSv (13%) were found across kVp levels (p < 0.00001). Maximum noise increase with OBTCM was 0.8 HU. With the Canon system, anterior dose reductions of 6–10% and total dose reduction of 0.74–0.76 mSv across kVp levels (p < 0.001) were found with a maximum noise increase of 1.1 HU. For the Siemens system, dose increased by 22–51% anteriorly; except at 100 kVp where no dose difference was found. Noise decreased by 1 to 1.5 HU.ConclusionOrgan based tube current modulation is capable of anterior and total dose reduction with minimal loss of image quality in vendors that do not increase posterior dose.Implications for practiceThis research highlights the importance of being familiar with dose reduction technologies.  相似文献   
43.
44.
45.
ObjectiveTo evaluate differences in postoperative pain control and opioids requirement in thoracic surgical patients following implementation of an Enhanced Recovery after Thoracic Surgery protocol with a comprehensive postoperative pain management strategy.Material and MethodsA retrospective analysis of a prospectively maintained database of patients undergoing pulmonary resections by robotic thoracoscopy or thoracotomy from January 1, 2017, to January 31, 2019, was conducted. Multimodal pain management strategy (opioid-sparing analgesics, infiltration of liposomal bupivacaine to intercostal spaces and surgical sites, and elimination of thoracic epidural analgesia use in thoracotomy patients) was implemented as part of Enhanced Recovery after Thoracic Surgery on February 1, 2018. Outcome metrics including patient-reported pain levels, in-hospital and postdischarge opioids use, postoperative complications, and length of stay were compared before and after protocol implementation.ResultsIn total, 310 robotic thoracoscopy and 62 thoracotomy patients met the inclusion criteria. This pain management strategy was associated with significant reduction of postoperative pain in both groups with an overall reduction of postoperative opioids requirement. Median in-hospital opioids use (morphine milligram equivalent per day) was reduced from 30 to 18.36 (P = .009) for the robotic thoracoscopy group and slightly increased from 15.48 to 21.0 (P = .27) in the thoracotomy group. More importantly, median postdischarge opioids prescribed (total morphine milligram equivalent) was significantly reduced from 480.0 to 150.0 (P < .001) and 887.5 to 150.0 (P < .001) for the thoracoscopy and thoracotomy groups, respectively. Similar short-term perioperative outcomes were observed in both groups before and following protocol implementation.ConclusionsImplementation of Enhanced Recovery after Thoracic Surgery allows safe elimination of epidural use, better pain control, and less postoperative opioids use, especially a drastic reduction of postdischarge opioid need, without adversely affecting outcomes.  相似文献   
46.
47.
48.
Cardiovascular Drugs and Therapy - Major depressive disorder (MDD) and anxiety disorders (AD) are both highly prevalent among individuals with arrhythmia, ischemic heart disease, heart failure,...  相似文献   
49.
50.
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