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   3761397篇
  免费   288996篇
  国内免费   26713篇
耳鼻咽喉   51580篇
儿科学   114244篇
妇产科学   97359篇
基础医学   524141篇
口腔科学   106816篇
临床医学   356465篇
内科学   714880篇
皮肤病学   76887篇
神经病学   299506篇
特种医学   145347篇
外国民族医学   1282篇
外科学   553392篇
综合类   126657篇
现状与发展   78篇
一般理论   1418篇
预防医学   293185篇
眼科学   91943篇
药学   288414篇
  310篇
中国医学   22861篇
肿瘤学   210341篇
  2021年   38675篇
  2019年   35253篇
  2018年   46552篇
  2017年   36719篇
  2016年   39264篇
  2015年   47430篇
  2014年   65170篇
  2013年   88511篇
  2012年   121931篇
  2011年   130636篇
  2010年   77799篇
  2009年   71224篇
  2008年   116204篇
  2007年   122993篇
  2006年   124338篇
  2005年   121419篇
  2004年   111978篇
  2003年   107216篇
  2002年   103842篇
  2001年   171048篇
  2000年   177050篇
  1999年   150860篇
  1998年   45400篇
  1997年   41107篇
  1996年   39840篇
  1995年   38502篇
  1994年   35581篇
  1993年   32261篇
  1992年   116599篇
  1991年   112622篇
  1990年   108520篇
  1989年   104672篇
  1988年   96553篇
  1987年   94702篇
  1986年   89374篇
  1985年   85184篇
  1984年   64044篇
  1983年   54505篇
  1982年   32275篇
  1979年   58846篇
  1978年   41064篇
  1977年   34890篇
  1976年   32650篇
  1975年   34467篇
  1974年   42421篇
  1973年   40474篇
  1972年   37889篇
  1971年   34987篇
  1970年   32871篇
  1969年   30587篇
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
71.
The increased number of lymphocytes in airways during an asthmatic response is believed to be the result of increased recruitment of these cells. However, it is possible that a decreased apoptotic rate could also contribute to the increased number. The aim of the present study was to investigate whether allergen airway provocation influences the apoptotic phenotype of lung and peripheral blood lymphocytes (PBL) in subjects with atopic asthma. Bronchoalveolar lavage (BAL) lymphocytes and PBL from 12 asthmatic subjects previously challenged with allergen (n = 7) or saline (n = 5) were exposed to the apoptotic stimulus tributyltin (TBT) in vitro and assayed for apoptosis. Airway allergen provocation resulted in decreased sensitivity of BAL lymphocytes to TBT-induced apoptosis, with 42.2% (range 33.9-62.5%) apoptotic cells before challenge versus 23.5% (range 15.3-42.4%) after challenge, while PBL were unaffected. The increased apoptosis resistance correlated with higher numbers of Bcl-2-expressing lymphocytes. Interestingly, baseline caspase-3-like activity was significantly elevated in viable BAL lymphocytes compared with viable PBL, and was unaltered by allergen exposure. In conclusion, allergen inhalation renders bronchoalveolar lavage lymphocytes more resistant to apoptosis while peripheral blood lymphocytes were not influenced at all, indicating that the apoptotic phenotype of airway lymphocytes may play a role in asthmatic inflammation.  相似文献   
72.
73.
74.
75.
Endoscopic clips have been used mainly for control of gastrointestinal (GI) bleeding and occasionally for closure of GI perforations. However, closure of spontaneous esophageal perforation (Boerhaave's syndrome) by clipping has not been reported. We described successful non-surgical closure of spontaneous esophageal perforation by endoscopic clipping in a patient with bilateral pyopneumothorax and septicemia.  相似文献   
76.
77.
78.
79.
80.
CONTEXT: Although the nonmedical use of stimulant drugs such as cocaine and methamphetamine is increasingly common in many rural areas of the United States, little is known about the health beliefs of people who use these drugs. PURPOSE: This research describes illicit stimulant drug users' views on health and health-related concepts that may affect their utilization of health care services. METHODS: A respondent-driven sampling plan was used to recruit 249 not-in-treatment, nonmedical stimulant drug users who were residing in 3 rural counties in west central Ohio. A structured questionnaire administered by trained interviewers was used to collect information on a range of topics, including current drug use, self-reported health status, perceived need for substance abuse treatment, and beliefs about health and health services. FINDINGS: Participants reported using a wide variety of drugs nonmedically, some by injection. Alcohol and marijuana were the most commonly used drugs in the 30 days prior to the interview. Powder cocaine was used by 72.3% of the sample, crack by 68.3%, and methamphetamine by 29.7%. Fair or poor health status was reported by 41.3% of the participants. Only 20.9% of the sample felt they needed drug abuse treatment. Less than one third of the sample reported that they would feel comfortable talking to a physician about their drug use, and 65.1% said they preferred taking care of their problems without getting professional help. CONCLUSIONS: Stimulant drug users in rural Ohio are involved with a range of substances and hold health beliefs that may impede health services utilization.  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