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   702868篇
  免费   28699篇
  国内免费   499篇
耳鼻咽喉   7828篇
儿科学   23419篇
妇产科学   15506篇
基础医学   108863篇
口腔科学   13858篇
临床医学   60637篇
内科学   125822篇
皮肤病学   12547篇
神经病学   50168篇
特种医学   28615篇
外国民族医学   54篇
外科学   106884篇
综合类   9899篇
现状与发展   2篇
一般理论   108篇
预防医学   56262篇
眼科学   14639篇
药学   50663篇
  1篇
中国医学   1755篇
肿瘤学   44536篇
  2021年   3960篇
  2018年   27176篇
  2017年   21043篇
  2016年   23972篇
  2015年   6259篇
  2014年   7909篇
  2013年   11284篇
  2012年   22401篇
  2011年   37962篇
  2010年   28358篇
  2009年   20126篇
  2008年   34830篇
  2007年   38682篇
  2006年   17456篇
  2005年   18406篇
  2004年   19211篇
  2003年   19523篇
  2002年   17250篇
  2001年   22763篇
  2000年   23458篇
  1999年   19151篇
  1998年   5444篇
  1997年   4580篇
  1996年   4485篇
  1995年   4240篇
  1992年   14490篇
  1991年   15946篇
  1990年   16123篇
  1989年   15751篇
  1988年   14392篇
  1987年   14280篇
  1986年   13229篇
  1985年   12755篇
  1984年   9446篇
  1983年   8050篇
  1982年   4221篇
  1979年   8964篇
  1978年   6410篇
  1977年   5173篇
  1976年   5525篇
  1975年   6636篇
  1974年   7464篇
  1973年   7183篇
  1972年   6617篇
  1971年   6330篇
  1970年   5928篇
  1969年   5510篇
  1968年   5189篇
  1967年   4629篇
  1966年   3974篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
An ankylosed tooth can be suitable for obtaining orthodontic anchorage. However, if such a tooth lacks adequate clinical crown height, the anchorage will not be effective. In those situations surgical luxation or restorative crown augmentation is suggested. This case report is about the restorative treatment of an ankylosed, infraoccluded tooth to enhance the anchorage for forced orthodontic eruption of impacted maxillary canines. A crown augmentation in the form of a modified bilayered (sandwich) restoration using GIC, Composite resin and Silver amalgam on left maxillary first molar (26) was successful in sustaining the anchorage for forced eruption and alignment of impacted canines.  相似文献   
992.

Background  

This study aimed to investigate the signs of oral dryness in relation to different salivary variables and to correlate subjective complaints of oral dryness with salivary flow rate.  相似文献   
993.
We previously demonstrated that treatments with rIL-1 beta accelerated the onset and progression of CIA in mice. In the present study, it was observed that IL-1 also enhanced the development of CIA in rats. Like the mouse model, maximal incidence (80-100%) of arthritis occurred within 7 days after the first treatment with IL-1 in rats. Thus, the acceleration of CIA by IL-1 (IL-1 CIA) may be an improved model for the rapid screening of anti-inflammatory and/or anti-arthritic drugs. As a first step to determining the utility of the IL-1 CIA model as a drug screen, we examined the ability of various known anti-inflammatory and anti-arthritic drugs to modify the IL-1 mediated enhancement of CIA in both rats and mice. The results of these studies showed that when analyzed in the IL-1 CIA model, rats and mice exhibited differences in their responses to several of these drugs. For example, dexamethasone, cyclophosphamide, azathioprine, various non-steroidal anti-inflammatory drugs (NSAIDs) as well as methotrexate were found active in the IL-1 CIA of rats. By contrast, the NSAIDs were found to be less effective in suppressing the IL-1 accelerated disease in mice. In both rats and mice, cyclosporine A and several disease modifying anti-arthritic drugs failed to the prevent the development of CIA that was potentiated by IL-1. Thus, in the IL-1 CIA model NSAIDs appeared to be less active in mice than rats. In conclusion, because of the shorter latent period required for the development of arthritis in the IL-1 treated animals, the IL-1 accelerated CIA model in both mice and rats may be useful for screening anti-inflammatory or anti-arthritic compounds.  相似文献   
994.
Summary 4-amino-1-hydroxybutylidene-1,1-bis-phosphonate (AHButBP) was given intravenously (2.5–25 mg/day for 4 days) to 14 patients with Paget's disease of bone, five of whom had been treated with dichloromethylidene bisphosphonate (Cl2MBP) 32 months earlier. In the nine patients who had not been treated previously with bisphosphonates, the short course of AHButBP induced a suppression of serum alkaline phosphatase and urinary hydroxyproline values down to 30% of initial values. The biochemical suppression of the disease was sustained for 2–18 months and the time to relapse did correlate to the logarithm of the dose (P<0.001). In the five patients previously treated for Paget's disease, an apparent resistence to treatment with AHButBP was observed. However, in these patients both serum alkaline phosphatase and urinary hydroxyproline fell to or even below the nadir values which had previously been achieved with Cl2MBP, irrespective of the degree of relapse. Thus the degree of suppression of Paget's disease of bone, achievable after treatment with bisphosphonates, seems to be constant for each patient, such that normal levels of serum alkaline phosphatase and urinary hydroxyproline cannot usually be attained in patients with extremely active disease.  相似文献   
995.
Three hundred and seventeen recent clinical isolates were tested for in vitro susceptibility to the three cephalosporins available in India--cephalexin, cefazolin and cefotaxime by the Kirby--Bauer disc diffusion method. Cefazolin was the most effective cephalosporin against Gram positive cocci (71.8% sensitive) followed by cefotaxime (62.7%) and cephalexin (52.7%). Cefotaxime was very effective against commonly isolated Gram negative bacilli with only 10 (8.8%) isolates being resistant to it while 44 (39%) and 65 (57.5%) were resistant to cefazolin and cephalexin, respectively. All isolates of Pseudomonas aeruginosa were resistant to cephalexin and cefazolin and only 29 (32.6%) were sensitive to cefotaxime.  相似文献   
996.
997.
998.
999.
1000.
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