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   2171篇
  免费   81篇
  国内免费   5篇
耳鼻咽喉   56篇
儿科学   32篇
妇产科学   14篇
基础医学   212篇
口腔科学   45篇
临床医学   110篇
内科学   615篇
皮肤病学   16篇
神经病学   221篇
特种医学   83篇
外科学   419篇
综合类   4篇
预防医学   64篇
眼科学   14篇
药学   178篇
中国医学   11篇
肿瘤学   163篇
  2023年   14篇
  2022年   25篇
  2021年   39篇
  2020年   16篇
  2019年   31篇
  2018年   34篇
  2017年   21篇
  2016年   34篇
  2015年   43篇
  2014年   54篇
  2013年   61篇
  2012年   93篇
  2011年   129篇
  2010年   63篇
  2009年   44篇
  2008年   93篇
  2007年   137篇
  2006年   146篇
  2005年   126篇
  2004年   138篇
  2003年   120篇
  2002年   104篇
  2001年   81篇
  2000年   64篇
  1999年   63篇
  1998年   24篇
  1997年   17篇
  1996年   13篇
  1995年   7篇
  1994年   12篇
  1993年   10篇
  1992年   44篇
  1991年   45篇
  1990年   40篇
  1989年   28篇
  1988年   31篇
  1987年   22篇
  1986年   29篇
  1985年   22篇
  1984年   18篇
  1983年   21篇
  1980年   6篇
  1979年   16篇
  1978年   8篇
  1977年   7篇
  1976年   7篇
  1974年   5篇
  1971年   9篇
  1970年   6篇
  1967年   5篇
排序方式: 共有2257条查询结果,搜索用时 31 毫秒
101.
102.
Chemical investigation of the Okinawan soft coral Clavularia koellikeri resulted in the isolation of two new cembrane diterpenoids (1 and 2) and one new dollabelane diterpenoid, 3. Their structures were determined on the basis of the results of spectroscopic analysis. Compounds 1 and 3 were examined for in vitro growth-inhibition effects toward tumor cells.  相似文献   
103.
104.
105.
106.
We reviewed the cases of recurrent low output syndrome (LOS) after the weaning from mechanical circulatory support for postcardiotomy cardiogenic shock. Twelve patients were divide into 2 groups according to whether low output syndrome recurred or not, consisting of a recurrent low output syndrome (+) group [re-LOS (+) group, n = 6] and a recurrent low output syndrome (-) group [re-LOS (-) group, n = 6]. Between 2 groups, there was no statistical difference in preoperative left ventricular ejection fraction (LVEF), aortic closs-clamping time and cardiac index at the weaning from mechanical circulatory support. Only the LVEF at the weaning in the re-LOS (+) group was significantly less than that in the re-LOS (-) group (0.39 +/- 0.08 vs 0.62 +/- 0.19, p < 0.05). All patients in the re-LOS (-) group survived to discharge, while in the re-LOS (+) group, although 3 patients were re-supported by intra-aortic balloon pumping, 4 of 6 patients died of multiple organ failure and 2 survivors were in New York Heart Association class III. The results suggest that the key to survive to discharge after the weaning from mechanical circulatory support is whether the cardiac contraction could recover or not.  相似文献   
107.
A 79-year-old male patient complicated with aortobronchial fistula after replacement of descending thoracic aorta with ringed graft. He underwent replacement of the aortic arch using a four branched vascular graft and open stent grafting to replace the descending thoracic aorta after removing the ringed-graft through median sternotomy. This procedure is useful for patients as the left thoracotomy is risky and the distal anastomotic site of the descending thoracic aorta is too far to anastomose.  相似文献   
108.
OBJECTIVES: We investigated the clinical usefulness of soluble dietary fiber (SDF) for the treatment of diarrhea during enteral nutrition in elderly patients. METHODS: This study included 10 men and 10 women (mean age +/- standard deviation: 79.3 +/- 5.1 y) who had diarrhea during long-term nutrition management. When administering SDF, the initial dose was 7 g and thereafter gradually increased at 1-wk intervals. After 4 wk, the administration was discontinued for 2 wk to confirm the effects of SDF. RESULTS: After the administration of SDF, serum diamine oxidase activity significantly increased (P < 0.001): The water content of the feces decreased significantly after the administration of fiber (P < 0.01). The frequency of daily bowel movements also decreased significantly (P < 0.05). Simultaneously, the fecal features improved. Concerning intestinal flora, there were no significant changes in the total number of bacteria or the number of anaerobic bacteria. The fecal pH decreased significantly 4 wk after the administration of fiber (P < 0.05). The total level of short-chain fatty acids increased significantly 4 wk after the administration of fiber (P < 0.05). There were no significant changes in the various nutritional indices. CONCLUSIONS: The administration of SDF is useful for controlling spontaneous, favorable bowel movement by improving symptoms of small intestinal mucosal atrophy and normalizing the intestinal flora.  相似文献   
109.
Since the year 2000, our hospital has been equipped with an intensity modulated radiation therapy (IMRT) facility. Before IMRT is administered, the absorbed dose is measured by the ionization chamber to provide verification for the IMRT procedure. In utilizing the current point dose evaluation, large discrepancies have been experienced when the measured dose is compared with the calculated dose. This discrepancy is due to the lack of uniformity in IMRT irradiation in comparison with that of the present method of dose distribution. In order to reduce the margin of error, the average dose of the ionization chamber calculated on a dose-volume histogram was compared with the measured dose. As a result, the margin of error was minimized to <2% in uniform areas and <4% in non-uniform areas.  相似文献   
110.
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