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   1341369篇
  免费   112821篇
  国内免费   6362篇
耳鼻咽喉   16756篇
儿科学   43158篇
妇产科学   36600篇
基础医学   183909篇
口腔科学   36359篇
临床医学   120943篇
内科学   279162篇
皮肤病学   31912篇
神经病学   110737篇
特种医学   55614篇
外国民族医学   274篇
外科学   210612篇
综合类   31594篇
现状与发展   2篇
一般理论   416篇
预防医学   106948篇
眼科学   28113篇
药学   94178篇
  24篇
中国医学   2232篇
肿瘤学   71009篇
  2018年   13398篇
  2017年   10641篇
  2016年   12826篇
  2015年   14335篇
  2014年   19984篇
  2013年   29790篇
  2012年   36310篇
  2011年   38967篇
  2010年   24416篇
  2009年   23945篇
  2008年   36456篇
  2007年   38866篇
  2006年   39985篇
  2005年   38569篇
  2004年   36816篇
  2003年   35902篇
  2002年   33892篇
  2001年   66115篇
  2000年   67979篇
  1999年   56632篇
  1998年   16740篇
  1997年   15044篇
  1996年   16034篇
  1995年   16245篇
  1994年   15110篇
  1993年   14162篇
  1992年   47119篇
  1991年   45768篇
  1990年   43998篇
  1989年   41834篇
  1988年   38779篇
  1987年   38096篇
  1986年   35873篇
  1985年   34657篇
  1984年   26374篇
  1983年   22116篇
  1982年   13858篇
  1981年   12458篇
  1980年   11723篇
  1979年   23557篇
  1978年   17085篇
  1977年   14394篇
  1976年   13201篇
  1975年   13734篇
  1974年   16099篇
  1973年   15409篇
  1972年   14182篇
  1971年   13043篇
  1970年   11888篇
  1969年   11114篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
53.
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   
54.
55.
56.
57.
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   
58.
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   
59.
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   
60.
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