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   1680505篇
  免费   137462篇
  国内免费   2794篇
耳鼻咽喉   22596篇
儿科学   55051篇
妇产科学   47452篇
基础医学   237932篇
口腔科学   48197篇
临床医学   149857篇
内科学   331110篇
皮肤病学   34985篇
神经病学   137504篇
特种医学   67770篇
外国民族医学   477篇
外科学   256092篇
综合类   40788篇
现状与发展   3篇
一般理论   634篇
预防医学   129560篇
眼科学   38602篇
药学   126759篇
  3篇
中国医学   3069篇
肿瘤学   92320篇
  2018年   17094篇
  2016年   14662篇
  2015年   17073篇
  2014年   23580篇
  2013年   35231篇
  2012年   48500篇
  2011年   51031篇
  2010年   29832篇
  2009年   28335篇
  2008年   48014篇
  2007年   50519篇
  2006年   50995篇
  2005年   49476篇
  2004年   48477篇
  2003年   46256篇
  2002年   45016篇
  2001年   76531篇
  2000年   78989篇
  1999年   67197篇
  1998年   18550篇
  1997年   16957篇
  1996年   16839篇
  1995年   16503篇
  1994年   15534篇
  1993年   14666篇
  1992年   55879篇
  1991年   54194篇
  1990年   52932篇
  1989年   51201篇
  1988年   47536篇
  1987年   46866篇
  1986年   44566篇
  1985年   43152篇
  1984年   32324篇
  1983年   27828篇
  1982年   16448篇
  1981年   14715篇
  1980年   13785篇
  1979年   30667篇
  1978年   21289篇
  1977年   17941篇
  1976年   16837篇
  1975年   17686篇
  1974年   21629篇
  1973年   20794篇
  1972年   18964篇
  1971年   17870篇
  1970年   16376篇
  1969年   15360篇
  1968年   14029篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
993.
994.
Multiple options exist for the prevention of deep vein thrombosis (DVT) in medical inpatients. We sought to determine the cost-effectiveness of low-molecular-weight heparin (LMWH) relative to unfractionated heparin (UFH) for DVT prevention in this setting. We conducted a cost-effectiveness analysis from the perspective of a third-party payer employing a decision model and literature-based estimates for inputs. In the base-case analysis, LMWH had little impact on the rate of DVT. Despite higher acquisition costs, however, LMWHs resulted in net savings. Routine use of LMWH saves approximately US$89 per patient. The lower rate of heparin-induced thrombocytopenia (HIT) with LMWH accounted for this differential. Univariate sensitivity analysis revealed the model was moderately sensitive to the odds ratio of HIT with LMWH and the cost of HIT. Multivariate sensitivity analysis confirmed the LMWH approach dominated financially. 'Worst-case' scenario modeling, where LMWH actually increased the risk for DVT, had little effect on the rate of HIT, and was substantially more costly than UFH, still demonstrated that LMWHs were economically superior. Monte-Carlo simulation indicated the 95% confidence interval around the estimate for savings with LMWH ranged from US$7 to US$373. We conclude that, despite their higher cost, LMWHs for thromboprophylaxis in medical patients result in savings.  相似文献   
995.
996.
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   
997.
998.
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   
999.
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