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   1338825篇
  免费   94308篇
  国内免费   2940篇
耳鼻咽喉   19759篇
儿科学   40300篇
妇产科学   38776篇
基础医学   187641篇
口腔科学   39925篇
临床医学   112813篇
内科学   262893篇
皮肤病学   30269篇
神经病学   106559篇
特种医学   53869篇
外国民族医学   435篇
外科学   208703篇
综合类   31094篇
现状与发展   6篇
一般理论   437篇
预防医学   92186篇
眼科学   31398篇
药学   100261篇
  4篇
中国医学   2988篇
肿瘤学   75757篇
  2018年   11823篇
  2015年   11903篇
  2014年   16787篇
  2013年   25434篇
  2012年   33105篇
  2011年   34954篇
  2010年   20915篇
  2009年   20417篇
  2008年   33648篇
  2007年   36766篇
  2006年   37384篇
  2005年   36075篇
  2004年   35136篇
  2003年   34111篇
  2002年   33634篇
  2001年   63674篇
  2000年   65400篇
  1999年   55479篇
  1998年   14737篇
  1997年   13542篇
  1996年   13016篇
  1995年   12282篇
  1994年   11526篇
  1992年   42791篇
  1991年   41323篇
  1990年   40587篇
  1989年   39599篇
  1988年   36992篇
  1987年   36443篇
  1986年   34949篇
  1985年   33156篇
  1984年   24851篇
  1983年   21091篇
  1982年   12691篇
  1981年   11601篇
  1980年   10797篇
  1979年   23947篇
  1978年   17085篇
  1977年   14848篇
  1976年   13398篇
  1975年   15278篇
  1974年   18088篇
  1973年   17567篇
  1972年   16822篇
  1971年   15721篇
  1970年   14920篇
  1969年   14354篇
  1968年   13470篇
  1967年   12019篇
  1966年   11265篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
995.
996.
997.
OBJECTIVE: In Japan, the incidence of both colorectal carcinoma and vascular disease is increasing. We screened preoperative patients with abdominal aortic aneurysm (AAA) or peripheral artery disease (PAD) for colorectal cancer. DESIGN OF STUDY: This study was retrospective and cross-sectional. MATERIALS: The subjects were 492 patients admitted for elective surgery of AAA or PAD. METHODS: The patients underwent immunochemical faecal occult blood tests (FOBT) before operation, and those with positive results underwent investigations for colorectal neoplasm. We compared the results with that of screening programmes performed on the general population. RESULTS: Of the 408 patients that underwent FOBT, 104 (25.5%) were positive. After colonoscopy, six (1.5%) had colorectal carcinoma and 16 (3.9%) had advanced adenoma. These values were several folds higher than that for the general population in Japan. CONCLUSIONS: Patients with AAA or PAD carry a high risk for colorectal neoplasm.  相似文献   
998.
OBJECTIVES: Local anaesthetic infiltration into the carotid sinus during carotid endarterectomy (CEA) has been recommended to minimise blood pressure fluctuations but its use remains controversial. The aim of this meta-analysis was to determine whether intra-operative administration of local anaesthetic reduces the incidence of haemodynamic instability following CEA. MATERIALS AND METHODS: A search of the Medline, Pubmed and Embase databases and the Current Controlled Trials register identified four trials, which met the pre-defined inclusion criteria for data extraction. Pooled odds ratios with 95 per cent confidence intervals (c.i.) for the development of post-operative hypotension and hypertension were calculated using a random-effects model. RESULTS: Outcomes of 432 patients were studied. Local anaesthetic blockade of the carotid sinus was associated with a pooled odds ratio of 1.25 (95 per cent c.i. 0.496 to 3.15); p=0.216) and 1.28 (95 per cent c.i. 0.699 to 2.33; p=0.428) for the development of post-operative hypotension and hypertension respectively. Although none reach significance there was a trend towards increased risk of developing a complication in those patients who received local anaesthetic. CONCLUSIONS: There are insufficient data to determine the role of intra-operative local anaesthetic administration in reducing post-operative blood pressure lability following CEA. Conversely, the possibility of harm cannot be excluded on the basis of the currently available data.  相似文献   
999.
By oxygen concentration measurements (Oximeter Oxydig Dräger, Lübeck) in the EC 145 helicopter two oxygen transport and application systems were compared. The new liquid oxygen system (LOX) for the oxygen therapy was assessed in an application observation. For physical reasons fluid oxygen evaporates during the stand-by phase and an increased concentration (22.8% O2) in the exhaust valve of LOX arises. On the other hand a high oxygen concentration (22.7% O2) was measured in the operation mode of the conventional pressure flask gas system (GAS). No increased concentration could be measured within the helicopter cabin (HEMS, PAX) comparing both oxygen systems. For transport and application of oxygen with a very big reserve for the air dependent intensive transport the results show that LOX is a sure low pressure system (3.4 bar).  相似文献   
1000.
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