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   1601645篇
  免费   131521篇
  国内免费   2582篇
耳鼻咽喉   21646篇
儿科学   52940篇
妇产科学   46227篇
基础医学   227761篇
口腔科学   47200篇
临床医学   140906篇
内科学   314762篇
皮肤病学   34090篇
神经病学   130111篇
特种医学   64722篇
外国民族医学   474篇
外科学   243804篇
综合类   39712篇
现状与发展   3篇
一般理论   544篇
预防医学   122859篇
眼科学   36470篇
药学   121253篇
  3篇
中国医学   2974篇
肿瘤学   87287篇
  2018年   14765篇
  2016年   12898篇
  2015年   15026篇
  2014年   20646篇
  2013年   31352篇
  2012年   42550篇
  2011年   44748篇
  2010年   26336篇
  2009年   25302篇
  2008年   43001篇
  2007年   45242篇
  2006年   46049篇
  2005年   44674篇
  2004年   44091篇
  2003年   42180篇
  2002年   41298篇
  2001年   75683篇
  2000年   78328篇
  1999年   66391篇
  1998年   17732篇
  1997年   16334篇
  1996年   16314篇
  1995年   16019篇
  1994年   15070篇
  1993年   14217篇
  1992年   55427篇
  1991年   53775篇
  1990年   52561篇
  1989年   50832篇
  1988年   47221篇
  1987年   46560篇
  1986年   44284篇
  1985年   42843篇
  1984年   32034篇
  1983年   27565篇
  1982年   16144篇
  1981年   14436篇
  1980年   13564篇
  1979年   30460篇
  1978年   21064篇
  1977年   17764篇
  1976年   16694篇
  1975年   17574篇
  1974年   21486篇
  1973年   20672篇
  1972年   18853篇
  1971年   17770篇
  1970年   16289篇
  1969年   15268篇
  1968年   13949篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
982.
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   
983.
984.
OBJECTIVE: The authors described the influence of specific medical conditions on clinical remission and response of major depression (MDD) in a clinical trial evaluating a care-management intervention among older primary-care patients. METHODS: Adults age 60 years and older were randomly selected and screened for depression. Participants were randomly assigned to Usual Care or to an Intervention with a depression care-manager offering algorithm-based care for MDD. In all, 324 adults meeting criteria for MDD were included in these analyses. Remission and response was defined by a score on the Hamilton Rating Scale for Depression <10 and by a decrease from baseline of > or =50%, respectively. Medical comorbidity was ascertained through self-report. Cognitive impairment was defined by a score <24 on the Mini-Mental State Exam (MMSE). RESULTS: In Usual Care, rates of remission were faster in persons who reported atrial fibrillation (AF) than in persons who did not report AF and slower in persons who reported chronic pulmonary disease than in persons who did not report chronic pulmonary disease; rates of response were less stable in persons with MMSE <24 than in those with MMSE > or =24. In the Intervention condition, none of the specific chronic medical conditions were significantly associated with outcomes for MDD. CONCLUSIONS: Because disease-specific findings were observed in persons who received Usual Care but not in persons who received more intensive treatment in the Intervention condition, our results suggest that the association of medical comorbidity and treatment outcomes for MDD may be determined by the intensity of treatment for depression.  相似文献   
985.
986.
987.
988.
Chronic hepatitis B virus (HBV) infection affects about 200–400 million people worldwide and represents one of the leading causes for liver cirrhosis and hepatocellular carcinoma. Control over the HBV infection is achieved mainly by vaccination with Hepatitis B surface antigen (HBsAg). HBsAg contains N -linked glycosylation side and is recognized by both MBL-A and MBL-C in a Ca-dependent manner. HbsAg–MBL complexes activate complement and may thus affect humoural immunity. To investigate the role of MBL in humoural responses to HBsAg, we immununized mice that lack both MBL-A and MBL-C proteins with soluble HBsAg. It has been shown that deficiencies in other complement components like C1q, C4 and C3 result in decreased antibody responses. However, MBL double KO animals mounted dramatically increased humoural responses. After priming, MBL double KOs mounted HbsAg-specific IgM responses, which were threefold higher than WT controls. After boosting the HBsAg, total IgG was 10-fold higher in MBL KO than in WT control animals. Similar to the response to HbsAg, other glycosylated soluble antigens (e.g. invertase) induced better humoural responses in MBL double KO animals, suggesting that MBL plays an important role in a negative feedback regulation of adaptive immunity. Reconstitution experiments with rMBL partially rescued the KO phenotype. We propose that the clearance of glycoprotein antigens in MBL KO is handled differently from the WT, resulting in better stimulation of humoural responses. Alternatively, glycoprotein-Ag-MBL-rich complexes inhibit B-cell responsiveness via putative MBL receptors.  相似文献   
989.
990.
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