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   3520713篇
  免费   266769篇
  国内免费   6878篇
耳鼻咽喉   49733篇
儿科学   112117篇
妇产科学   94658篇
基础医学   495688篇
口腔科学   103119篇
临床医学   320712篇
内科学   681202篇
皮肤病学   74894篇
神经病学   286190篇
特种医学   136554篇
外国民族医学   1084篇
外科学   531053篇
综合类   83994篇
现状与发展   5篇
一般理论   1394篇
预防医学   278430篇
眼科学   84219篇
药学   262376篇
  11篇
中国医学   7487篇
肿瘤学   189440篇
  2018年   37568篇
  2017年   28714篇
  2016年   31765篇
  2015年   35996篇
  2014年   51158篇
  2013年   76921篇
  2012年   104752篇
  2011年   110733篇
  2010年   65581篇
  2009年   61939篇
  2008年   104119篇
  2007年   110911篇
  2006年   111864篇
  2005年   108518篇
  2004年   104542篇
  2003年   100304篇
  2002年   98094篇
  2001年   166754篇
  2000年   172007篇
  1999年   144796篇
  1998年   41123篇
  1997年   36679篇
  1996年   36343篇
  1995年   35161篇
  1994年   32822篇
  1993年   30424篇
  1992年   114834篇
  1991年   111169篇
  1990年   107273篇
  1989年   103617篇
  1988年   95684篇
  1987年   93982篇
  1986年   88846篇
  1985年   84752篇
  1984年   63812篇
  1983年   54376篇
  1982年   32215篇
  1981年   28770篇
  1979年   58790篇
  1978年   41064篇
  1977年   34890篇
  1976年   32650篇
  1975年   34468篇
  1974年   42422篇
  1973年   40474篇
  1972年   37890篇
  1971年   34987篇
  1970年   32871篇
  1969年   30589篇
  1968年   28087篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
The PFA-100 is a relatively new laboratory instrument, first described in 1995. There have since been numerous studies assessing its utility as a screening tool for platelet dysfunction and/or von Willebrand's disease (VWD). The PFA-100 displays variable sensitivity to different types of platelet disorders, as well as to antiplatelet medication (e.g. aspirin), with similar caveats for monitoring of primary haemostasis-promoting therapies in platelet dysfunction. There is therefore considerable uncertainty regarding its utility within this context, and we have accordingly performed an audit of usage among participants of the Royal College of Pathologists of Australasia Quality Assurance Program. Of 105 laboratories surveyed, 40 responded that they performed platelet function testing, with 26 (65%) further indicating they utilized the PFA-100. We report a wide variety of laboratory usage among these users, including numbers of tests performed [annual median (range) = 270 (15-6000)], sources of requests (clinical sources and localities), testing criteria and follow-up action. Most tests were completed within 4 h of collection, as recommended by the manufacturer, and most tests were performed as a replacement, or as a preliminary screen of platelet function (i.e. classical aggregation). Most abnormal findings, however, were attributed to antiplatelet medication such as aspirin.  相似文献   
995.
996.
From 1975 to 2004 a total of 38 children handicapped by congenital multiple arthrogryposis were cared for. The congenital joint contractures demand a major effort in terms of surgical reconstruction. In the case of distal arthrogryposis the chances that patients will be able to walk without help are good, while those with amyoplasia are likely to be dependent on mobility aids throughout their lives. The ultimate goal of treatment for patients is to develop into self-confident adults who can cope with life despite their handicaps. The hip in arthrogryposis shows variable forms of pathology, ranging from the almost normal hip to hip contractures with dislocation. Its treatment has some limited advantages, but hardly improves mobility. The knee contractures are actively treated to allow patients to sit, stand and walk better. The club foot and the rocker-bottom foot need sophisticated conservative and operative treatments. If conservative manipulation of bilateral extension contractures of the elbow fails operative treatment is carried out on the dominant side. For shoulder, hand and finger contractures conservative manipulation brings about little improvement, and surgical approaches help hardly at all.  相似文献   
997.
998.
999.
1000.
BACKGROUND: Although many histopathologic factors in squamous cell carcinoma of the tongue predict the prognosis, the major predictive factors have not been identified clearly. This study analyzed the prognostic value of the histologic grade at the deep invasive front of tongue squamous cell carcinoma. METHODS: The clinicopathologic features of 124 consecutive patients seen between January 1985 and December 1999 with previously untreated squamous cell carcinoma of the tongue were reviewed. Their mean age was 58.5 years (range: 23-90) and the male-female ratio was 1.8: 1 (79 men and 45 women). There were 41, 40, 30, and 13 cases at stage I to stage IV, respectively. The clinicopathologic factors, especially the histologic grade at the deep invasive front (invasive front grade, IFG), were analyzed to determine factors predicting prognosis. RESULTS: The 5-year disease-free survival rate of the patients treated with curative aim only was 66.7%. Clinicopathologic factors significantly associated with the prognosis were T classification, tumor size, stage classification, tumor depth, macroscopic appearance, cervical lymph node metastasis (nodal metastasis), microvascular invasion, and IFG. In a multivariate analysis, patients with tumor depth >/=4 mm, IFG >/=8 points, and nodal metastasis had a reduced disease-free survival and IFG >/=11 points had a predictive value for nodal metastasis (odds ratio: 7.34; P = 0.0019). CONCLUSION: This study found that a high IFG malignancy score had a high prognostic value for squamous cell carcinoma of the tongue.  相似文献   
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