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   1338585篇
  免费   112542篇
  国内免费   6371篇
耳鼻咽喉   16705篇
儿科学   43006篇
妇产科学   36554篇
基础医学   183629篇
口腔科学   36275篇
临床医学   120719篇
内科学   278550篇
皮肤病学   31898篇
神经病学   110508篇
特种医学   55535篇
外国民族医学   274篇
外科学   210363篇
综合类   31545篇
现状与发展   2篇
一般理论   414篇
预防医学   106651篇
眼科学   28086篇
药学   93712篇
  5篇
中国医学   2227篇
肿瘤学   70840篇
  2018年   13380篇
  2017年   10632篇
  2016年   12796篇
  2015年   14306篇
  2014年   19948篇
  2013年   29741篇
  2012年   36249篇
  2011年   38889篇
  2010年   24376篇
  2009年   23906篇
  2008年   36373篇
  2007年   38782篇
  2006年   39903篇
  2005年   38488篇
  2004年   36726篇
  2003年   35824篇
  2002年   33841篇
  2001年   66052篇
  2000年   67919篇
  1999年   56588篇
  1998年   16724篇
  1997年   15019篇
  1996年   16016篇
  1995年   16233篇
  1994年   15099篇
  1993年   14153篇
  1992年   47099篇
  1991年   45750篇
  1990年   43972篇
  1989年   41819篇
  1988年   38762篇
  1987年   38085篇
  1986年   35861篇
  1985年   34635篇
  1984年   26363篇
  1983年   22114篇
  1982年   13849篇
  1981年   12452篇
  1980年   11718篇
  1979年   23544篇
  1978年   17074篇
  1977年   14386篇
  1976年   13182篇
  1975年   13723篇
  1974年   16094篇
  1973年   15397篇
  1972年   14173篇
  1971年   13036篇
  1970年   11880篇
  1969年   11101篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
61.
62.
63.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  相似文献   
64.
65.
66.
67.
For many parents stopping life-sustaining medical treatment on their dying infant is psychologically impossible. Dostoevsky's insights into human behavior, particularly the fact that individuals do not want the anxiety and guilt associated with responsibility for making difficult decisions, might change the way physicians approach parents for permission to withdraw life-prolonging medical interventions on dying infants.  相似文献   
68.
Four clinical trials of porcine islet transplantation have been reported, and there are verbal reports that clinical trials on much larger scales are continuing in centers in China and Russia. The four reported trials are briefly reviewed and, in the light of the present status of experimental islet xenotransplantation, consideration is given to whether such trials are currently justified. The Ethics Committee of the International Xenotransplantation Association has (1) emphasized the need for encouraging studies in non-human primates before clinical trials should be undertaken, (2) mandatory monitoring for the transfer of porcine microorganisms, and (3) careful regulation and oversight by recognized bodies. Other aspects of the topic, such as the need for informed consent, are briefly discussed. We conclude that, at the present time, more data documenting convincing efficacy, focused on clinically applicable immunosuppressive regimens, are needed to justify the initiation of closely monitored clinical trials. A clinical trial may then be justified even though the potential risk to the patients, and possibly for society, will not be zero.  相似文献   
69.
Summary: The mosaic (Atp7a mo-ms ) is an X-linked, lethal mutation in mice. In mosaic mutant males, many clinical features characteristic of defective copper metabolism have been observed and they die at the age of 15 days, exhibiting strongsimilarities to the brindled and macular mutants. About 4% of the mutant males live to sexual maturity and some of them are fertile. In this paper, alterationsin the structure of the kidney from adult mutants are described. Owing to an inherited defect of efflux, copper is accumulated in the kidney of the mutants up to a toxic level and this leads to severe damage of the renal cortex. Pathological changes in the kidney mostly affected the structure of the renal corpuscle and renaltubules.  相似文献   
70.
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