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   1918篇
  免费   141篇
  国内免费   11篇
耳鼻咽喉   11篇
儿科学   36篇
妇产科学   17篇
基础医学   249篇
口腔科学   28篇
临床医学   256篇
内科学   292篇
皮肤病学   11篇
神经病学   305篇
特种医学   274篇
外科学   103篇
综合类   41篇
预防医学   165篇
眼科学   21篇
药学   161篇
中国医学   2篇
肿瘤学   98篇
  2021年   27篇
  2020年   13篇
  2019年   16篇
  2018年   23篇
  2017年   20篇
  2016年   22篇
  2015年   24篇
  2014年   29篇
  2013年   49篇
  2012年   68篇
  2011年   62篇
  2010年   36篇
  2009年   43篇
  2008年   68篇
  2007年   78篇
  2006年   67篇
  2005年   51篇
  2004年   68篇
  2003年   85篇
  2002年   60篇
  2001年   61篇
  2000年   64篇
  1999年   55篇
  1998年   38篇
  1997年   40篇
  1996年   29篇
  1995年   30篇
  1994年   42篇
  1993年   34篇
  1992年   48篇
  1991年   39篇
  1990年   42篇
  1989年   59篇
  1988年   56篇
  1987年   62篇
  1986年   52篇
  1985年   54篇
  1984年   58篇
  1983年   33篇
  1982年   30篇
  1981年   31篇
  1980年   28篇
  1979年   24篇
  1978年   30篇
  1977年   17篇
  1976年   22篇
  1975年   15篇
  1974年   6篇
  1972年   6篇
  1969年   6篇
排序方式: 共有2070条查询结果,搜索用时 46 毫秒
101.
Ambulatory blood pressure monitoring (ABPM) in adults is proving to be useful. The aim of this study was to determine if ABPM is accurate in the lower blood pressure range encountered in children and, equally important, whether it is acceptable to children. Thirty one children, between the ages of 6 and 18 years, were assessed using an ambulatory blood pressure monitor that uses an auscultatory method. Blood pressure was measured in the contralateral arm with a mercury sphygmomanometer and an oscillometric device at the beginning and end of the study for comparison. Over a blood pressure range of 90-130 mm Hg systolic and 40-80 mm Hg diastolic, a close agreement was found with the sphygmomanometer; the limits of agreement (+/- 2 SD) were 11.6 mm Hg for systolic blood pressure and 13.6 mm Hg for diastolic blood pressure. The bias was less than 1.0 mm Hg. The ambulatory device was worn by all patients for at least 16 hours with an average of 52 recordings per patient. The majority found the device comfortable to wear and were not woken from sleep.  相似文献   
102.
Magnetic resonance imaging of benign mediastinal masses   总被引:1,自引:0,他引:1  
  相似文献   
103.
P K Coyle  M Bulbank 《Neurology》1989,39(3):378-380
External secretions from multiple sclerosis (MS) patients show immunoglobulin abnormalities consistent with mucosal inflammation. In this study we collected tears and parotid saliva from ten normal subjects and ten MS patients to examine for free-floating inflammatory cells. We found lymphocytes, macrophages, and plasma cells at low numbers in normal secretions, but at much higher numbers in MS secretions. Using an immunobead rosette technique, most of the lymphocytes were null cells. However, we found increased T lymphocytes in the secretions of clinically active MS patients. The extensive mucosal surfaces of the MS patient could provide a peripheral source for activated lymphocytes that subsequently enter brain.  相似文献   
104.
This report indicates that not only does the preoperative administration of cyclophosphamide or radiation prevent the kinetic changes observed in a distant tumor focus following tumor removal but that the preoperative administration of the antiestrogen tamoxifen and the luteinizing hormone-releasing hormone analogue Zoladex are equally effective in that regard. It also provides evidence indicating that serum obtained from mice treated with those therapies when transferred to a recipient bearing a tumor of a similar type to that in the donor fails to stimulate DNA synthesis in the tumor of the recipient. In contrast, an increase in labeling index occurs following transfer of serum obtained following tumor removal from untreated mice. Moreover, when tumor-bearing mice were treated by each of the four modalities prior to receiving serum obtained from untreated donors following removal of a tumor, no kinetic changes were observed in the tumor of the serum recipient.  相似文献   
105.
Tidwell  T; Guzman  G; Vogler  WR 《Blood》1981,57(4):794-797
The action of an alkyl-lysophospholipid (ALP), ET180CH3, on clonogenicity, 3H-TdR uptake, and cell numbers was tested in two human leukemic cell lines, HL60 and K562, and short-term human leukemic bone marrow cultures. ALP eliminated clonogenicity in HL60 but not in K562 cultures; 3H-TdR uptake and cell numbers were depressed at low concentrations of ET180CH3 in HL60, but not K562 cultures. The action of the lysophospholipid analog on human leukemic bone marrow short-term cultures at low concentrations was similar to its action on HL60 cultures; clonogenicity and 3H-TdR uptake were depressed, but cell numbers were not significantly affected. The demonstration of differential action of ALP on two cell lines should significantly simplify the investigation of the mechanism of the reported differential action of ET180CH3 on normal and leukemic cell membranes.  相似文献   
106.
107.
108.
109.
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