首页 | 官方网站   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   1689948篇
  免费   126450篇
  国内免费   3771篇
医药卫生   1820169篇
  2021年   12770篇
  2019年   13522篇
  2018年   19955篇
  2017年   15214篇
  2016年   16612篇
  2015年   18959篇
  2014年   26219篇
  2013年   37946篇
  2012年   52737篇
  2011年   55424篇
  2010年   32780篇
  2009年   30701篇
  2008年   51518篇
  2007年   54804篇
  2006年   55259篇
  2005年   52544篇
  2004年   50747篇
  2003年   48155篇
  2002年   46373篇
  2001年   91786篇
  2000年   93610篇
  1999年   76965篇
  1998年   19718篇
  1997年   17267篇
  1996年   17392篇
  1995年   16744篇
  1994年   15290篇
  1993年   14071篇
  1992年   57381篇
  1991年   55274篇
  1990年   52973篇
  1989年   50748篇
  1988年   46133篇
  1987年   44938篇
  1986年   42228篇
  1985年   39989篇
  1984年   29348篇
  1983年   24908篇
  1982年   13898篇
  1979年   25467篇
  1978年   17531篇
  1977年   14849篇
  1976年   13830篇
  1975年   14514篇
  1974年   17602篇
  1973年   16908篇
  1972年   15664篇
  1971年   14433篇
  1970年   13415篇
  1969年   12504篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Spinal antinociceptive effects of adenosine compounds in mice   总被引:1,自引:0,他引:1  
The effects of injecting ATP, ADP, AMP, adenosine and adenine intrathecally on the pain response induced by the injection of substance P (10 ng/mouse) intrathecally were studied. All the compounds except adenine inhibited the pain response in a dose-related manner. The ED50 values of ATP, ADP, AMP and adenosine were 2.10, 0.93, 0.88 and 0.48 micrograms/mouse, respectively. Pretreatment with theophylline at a dose of 100 mg/kg p.o. markedly diminished all the antinociceptive effects. The effect of adenosine was not affected by s.c. injection of naloxone. These results suggest the existence of adenosine receptors which modulate spinal nociceptive sensory processing, independently of the endogenous opiate system.  相似文献   
982.
Reported in this paper are postoperative results recorded from 120 patients, 3 years after selective proximal vagotomy for uncomplicated duodenal ulcer. There was no intraoperative lethality and no recurrence in 96.7 per cent of all cases, while Visick grades I on II were recorded from 98.2 per cent. Radiologically and gastroscopically detected pathological processes receded soon. Average postoperative reduction in acid secretion was 66.2 per cent in BAO and 46.8 per cent in MAO. Acid values re-increased thereafter, and three years later reduction rates still amounted to 43.7 per cent in BAO and 28.6 per cent in MAO. Indications for proximal gastric vagotomy are discussed in some detail.  相似文献   
983.
984.
Experience with the 'skew flap' below-knee amputation   总被引:3,自引:0,他引:3  
A review of 353 lower limb amputations over the last 7 years has been performed to assess the results of the skew flap myoplastic below-knee amputation which was introduced in April 1983 because of reported advantages in terms of wound healing and earlier ambulation. Comparing the first 3 1/2 year period with the second, the total number of amputations decreased by 31 per cent. The number of above-knee amputations remained similar in the two periods (82,62), whilst the number of Gritti-Stokes amputations fell from 79 to 21 (0.001 greater than P greater than 0.01). The proportion of below-knee (BK) amputations increased from 50 (23.7 per cent) to 59 (41.5 per cent) (0.01 greater than P greater than 0.025). The groups were comparable in terms of previous vascular surgery and co-existing medical conditions. The time to full stump healing was significantly shorter in the skew flap group compared with the earlier Burgess type BK amputation (P = 0.001), and there was a trend to fewer stump failures in the skew flap group. We therefore feel that the skew flap amputation gives superior results to the Burgess BK amputation in terms of healing and a lower complication rate, allowing a higher proportion of BK amputations to be performed. A prospective randomized trial of the two techniques is in hand to determine the accuracy of this hypothesis.  相似文献   
985.
Topical analgesia for relief of post-circumcision pain   总被引:1,自引:0,他引:1  
  相似文献   
986.
987.
Three evaluation instruments (global, check-list, and criterion referenced) were used by experienced and inexperienced examiners to evaluate dental sealant end products on 40 extracted teeth. Intra- and interexaminer reliabilities were measured. Experienced examiners achieved higher intrarater reliabilities with all three evaluation instruments than did inexperienced examiners. The highest intraexaminer agreement for all examiners occurred with use of the global evaluation. The highest interexaminer reliability was achieved with the second use of the criterion-referenced evaluation by the experienced examiner. Interexaminer reliability was improved for both types of examiners with the criterion-referenced evaluation.  相似文献   
988.
A 65-year-old man with spontaneous rupture of the esophagus survived with a direct suture of the esophagus 15 hours after the onset of symptoms. Endoscopic examination of the esophagus was especially of great help in determining the surgical procedure in this patient, and we want to stress the importance of prompt diagnosis and immediate surgery for this disease.  相似文献   
989.
990.
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-23

京公网安备 11010802026262号