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   1338339篇
  免费   94111篇
  国内免费   2908篇
耳鼻咽喉   19719篇
儿科学   40282篇
妇产科学   38697篇
基础医学   187329篇
口腔科学   39849篇
临床医学   112900篇
内科学   262670篇
皮肤病学   30228篇
神经病学   106583篇
特种医学   54172篇
外国民族医学   435篇
外科学   208657篇
综合类   31077篇
现状与发展   6篇
一般理论   438篇
预防医学   92198篇
眼科学   31364篇
药学   100089篇
  4篇
中国医学   2987篇
肿瘤学   75674篇
  2018年   11780篇
  2015年   11892篇
  2014年   16727篇
  2013年   25301篇
  2012年   33078篇
  2011年   34952篇
  2010年   20792篇
  2009年   20278篇
  2008年   33658篇
  2007年   36787篇
  2006年   37348篇
  2005年   36114篇
  2004年   35175篇
  2003年   34146篇
  2002年   33659篇
  2001年   63683篇
  2000年   65385篇
  1999年   55452篇
  1998年   14679篇
  1997年   13480篇
  1996年   12969篇
  1995年   12244篇
  1994年   11489篇
  1992年   42832篇
  1991年   41334篇
  1990年   40611篇
  1989年   39617篇
  1988年   37034篇
  1987年   36472篇
  1986年   34960篇
  1985年   33151篇
  1984年   24864篇
  1983年   21073篇
  1982年   12679篇
  1981年   11582篇
  1980年   10787篇
  1979年   23942篇
  1978年   17104篇
  1977年   14856篇
  1976年   13404篇
  1975年   15291篇
  1974年   18099篇
  1973年   17568篇
  1972年   16812篇
  1971年   15721篇
  1970年   14921篇
  1969年   14349篇
  1968年   13462篇
  1967年   12023篇
  1966年   11260篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
172.
A national conference on organ donation after cardiac death (DCD) was convened to expand the practice of DCD in the continuum of quality end-of-life care. This national conference affirmed the ethical propriety of DCD as not violating the dead donor rule. Further, by new developments not previously reported, the conference resolved controversy regarding the period of circulatory cessation that determines death and allows administration of pre-recovery pharmacologic agents, it established conditions of DCD eligibility, it presented current data regarding the successful transplantation of organs from DCD, it proposed a new framework of data reporting regarding ischemic events, it made specific recommendations to agencies and organizations to remove barriers to DCD, it brought guidance regarding organ allocation and the process of informed consent and it set an action plan to address media issues. When a consensual decision is made to withdraw life support by the attending physician and patient or by the attending physician and a family member or surrogate (particularly in an intensive care unit), a routine opportunity for DCD should be available to honor the deceased donor's wishes in every donor service area (DSA) of the United States.  相似文献   
173.
174.
175.
176.
177.
Abstract Chorea is a rare complication of polycythaemia vera. Polycythaemic chorea occurs predominantly in females and usually in generalised form. We present a 66-year-old woman with acute onset hemichorea-ballism with no vascular pathology in the basal ganglia region. A clear relationship was observed between the onset of chorea and worsening of haematological parameters in the patient. After repeated phlebotomies the patient's clinical status was improved. Polycythaemic chorea must be considered, especially in the elderly, as early diagnosis leads to effective treatment and prevention of complications.  相似文献   
178.
179.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section.  相似文献   
180.
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