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   16094篇
  免费   1612篇
  国内免费   200篇
耳鼻咽喉   137篇
儿科学   444篇
妇产科学   305篇
基础医学   1905篇
口腔科学   282篇
临床医学   2019篇
内科学   2952篇
皮肤病学   189篇
神经病学   1339篇
特种医学   516篇
外国民族医学   1篇
外科学   1753篇
综合类   1345篇
现状与发展   2篇
一般理论   9篇
预防医学   1829篇
眼科学   233篇
药学   1400篇
  2篇
中国医学   346篇
肿瘤学   898篇
  2022年   166篇
  2021年   338篇
  2020年   228篇
  2019年   255篇
  2018年   229篇
  2017年   234篇
  2016年   223篇
  2015年   321篇
  2014年   426篇
  2013年   586篇
  2012年   828篇
  2011年   869篇
  2010年   656篇
  2009年   619篇
  2008年   742篇
  2007年   828篇
  2006年   802篇
  2005年   707篇
  2004年   600篇
  2003年   563篇
  2002年   528篇
  2001年   505篇
  2000年   542篇
  1999年   437篇
  1998年   170篇
  1997年   149篇
  1996年   148篇
  1995年   139篇
  1994年   163篇
  1993年   139篇
  1992年   331篇
  1991年   324篇
  1990年   257篇
  1989年   257篇
  1988年   263篇
  1987年   260篇
  1986年   239篇
  1985年   218篇
  1984年   200篇
  1983年   177篇
  1982年   131篇
  1981年   113篇
  1979年   163篇
  1978年   152篇
  1977年   108篇
  1976年   130篇
  1974年   130篇
  1973年   169篇
  1972年   119篇
  1968年   104篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
目的:应用99mTc-DTPA肾动脉显像评价Stanford不同分型主动脉夹层患者术后左、右侧肾功能及总体肾功能受损程度,帮助临床制定进一步的治疗方案,改善患者预后。方法:回顾性分析2018年3月8日至2019年7月19日,在本院核医学科行99mTc-DTPA肾动态显像的主动脉夹层术后患者48例,评价患者双肾血流灌注、总肾小球滤过率(GFR)和分肾的GFR,比较Stanford主动脉夹层A型(简称A型)患者和主动脉夹层B型(简称B型)患者之间总肾功能及分肾功能,血肌酐、血尿素氮及血尿酸水平的差异。结果:B型患者术后总GFR低于A型患者(67.5 vs.80.6 m L/min,P<0.05),其中以左肾功能受损为著(30.9 vs.40.3 m L/min,P<0.05),差异有统计学意义。结论:肾动态显像对主动脉夹层术后患者早期评价肾功能有重要价值。主动脉夹层B型患者GFR较A型减低,且左侧肾GFR减低更明显,临床可以早期采取干预措施,改善主动脉夹层患者预后。  相似文献   
4.
The patellar ligament (PL) is an epiphyseal ligament and is part of the extensor complex of the knee. The ligament has gained attention due to its clinical relevance to autograft and tendinopathy. A variety of anatomical variations of the PL such as aplasia, numerical variations, and vascularity are being reported recently by clinicians and anatomists. The aim of this literature was to review the available literature to provide a consensus regarding anatomic variations of the PL, neurovasculature surrounding the PL, histology of the PL, and various aspects of PL measurements with relevance to the surgical considerations and sex and age-related differences. A narrative review of the patellar ligament was performed by conducting a detailed literature search and review of relevant articles. A total of 90 articles on the patellar ligament were included and were categorized into studies based on anatomical variations, neurovasculature, morphometrics, microanatomy, sex and age-related difference, and ACL reconstruction. The anatomical variations and morphometrics of the PL were found to correlate with the frequency of strain injuries, tendinopathy, and efficacy of the PL autograft in anterior cruciate ligament reconstruction. The sex differences in PL measurements and the effect of estrogen on collagen synthesis explained a higher incidence of patellar tendinopathy in women. An awareness of its variations enables careful selection of surgical incisions, thereby avoiding complications related to nerve injury. Accurate knowledge of the PL microanatomy assists in understanding the mechanism of ligament degeneration, rupture, autograft harvesting, and ligamentization results.  相似文献   
5.
Background: It is widely known that a proportion of university students use drugs. However, much less is known about how they source and supply their drugs. Objectives: In this article, we investigate student drug trading activity, including how they obtained their drugs, whether they sold drugs, and the extent to which their drug trading might be described as a form of “social supply”. Methods: A survey was conducted of all students across seven of the nine universities of Wales. In total, 7855 students submitted a questionnaire and 1877 of these reported drug use in the current academic year. All students who reported using one or more illegal drugs in the current academic year were asked how they obtained their drugs, how they funded their drug use, whether they had sold, traded or given away illegal drugs, along with their motives for drug trading. Results: The results showed that about half of users obtained drugs solely from friends and associates and one-fifth obtained them solely from external dealers. One-quarter used friends and associates as well as external markets. In many cases, supplying drugs amounted to sharing them or giving them away. However, over one-third of students said that they had sold drugs. Conclusions: Overall, the methods of sourcing and supplying drug among university students shares features of both “social supply” and “traditional” drug markets. We conclude that the student drug market investigated is best described as a “hybrid” combination of both.  相似文献   
6.
痤疮可辨为阴、阳两证。阳疮者,缘患者劳汗被寒、玄府闭合,汗脂凝聚日久不得外排,蕴热搏结气血而生疮化腐,疮症为热为痛,此为易治;阴疮者,由阳疮转化而来,缘患者外感寒风、内伤生冷,且医者又重用寒凉、失于托透,以至气血冰凝,久不溃脓或溃脓难出,此为难治。根据难治性痤疮临床表现,其多类属于阴疮,以阳虚表郁、邪闭毛窍为致病之关键,其中表郁毛窍、邪闭肌腠为病之标,阳虚阴凝为病之本。治疗当以温阳透发、祛邪外达为法。以麻黄附子细辛汤温阳化阴滞、发阳透毒治其本,待阴邪发越,即用火针强开门户、消疮排脓治其标。标本兼治、针药结合的方法治疗难治性痤疮在临床中能够安全有效地消除痤疮、改善皮损、降低复发率。  相似文献   
7.
8.
Background: Large randomized trials show that in appropriately selected patients with left ventricular dysfunction, implantable cardioverter-defibrillators (ICDs) can improve overall survival at 2–5 years. Since direct implementation of the criteria used in the MADIT II and SCD-HeFT will lead to a marked rise in ICD implants, there is a growing fear that increased use of ICDs may cause a dramatic burden to health care systems. The ICD has traditionally been seen as an expensive form of treatment, which is difficult to accept at the first look. This is mainly due to the nonlinear character of the ICD investment, characterized by high initial expenditure, followed by a deferred pay-off in terms of clinical benefits. Cost-effectiveness analysis may help provide a different perspective on the problem of ICD cost, as may estimation of the daily cost of ICD treatment, assuming a time horizon of 5–7 years—a particularly interesting subject for further registry studies.
Methods and Results: Based on real expenditure data from 2002 to 2005, as recorded in the Search-MI Registry-Italian Sub-study of patients implanted on MADIT II indications, we estimated the daily costs associated with the device and leads. Over a 5–7 year time horizon, the average daily cost was estimated to be €4.60–€6.70. Translation of these figures into U.S. market conditions suggests a daily cost of around $7.90–$11.40.
Conclusions: These findings appear useful to help evaluate the affordability of ICD in comparison with other therapeutic options in a context of limited available economic resources.  相似文献   
9.
目的 探讨P16、P15、P14基因5'CpG岛在膀胱移行细胞癌中甲基化状态及其临床意义。方法 应用甲基化特异性PCR(methylation—specific PCR,MSP)方法检测40例膀胱移行细胞癌P16、P15、P14基因甲基化程度,χ^2检验分析其甲基化程度与膀胱癌病理分级分期间关系。结果 膀胱移行细胞癌P16、P15、P14 5'CpG岛甲基化扩增阳性化率分别为27.5%、17.5%、35%,而正常膀胱组织中均未检测到三种基因5'CpG岛甲基化。P16、P14基因甲基化与膀胱癌病理分级分期有显著性差异(P〈0.05),P15基因则没有显著性差异(P〉0.05)。结论 P16、P15、P14基因在膀胱癌组织中的甲基化率较高,三种抑癌基因5'CpG岛异常高甲基化,在膀胱癌的发生、发展中具有重要作用。  相似文献   
10.
目的评价听觉诱发电位指数(AAI)、脑电双频指数(BIS)预测异丙酚麻醉下患者术中体动反应的可能性。方法择期行妇科手术全麻患者28例,ASAⅠ或Ⅱ级,年龄24-62岁,体重46- 71 kg,术前2 h口服咪达唑仑10 mg,入室后以血浆靶浓度3.5μg/ml靶控输注异丙酚、静脉注射芬太尼2μg/kg及维库溴铵0.1 mg/kg麻醉诱导,气管插管后,调整异丙酚血浆靶浓度维持BIS 40-60。切皮后不再追加肌松剂,观察患者术中头面部及四肢的体动反应,记录体动反应发生前、后2min内BIS、AAI的最大值(BISmax、AAImax)及此时段内BIS>75、AAI>40的次数及出现时间。记录术中当BIS>75、AAI>40时前、后2 min内有无体动反应发生及发生时间。结果12例出现体动反应,体动前、后2 min内BISmax为63±16(4例BIS>75,33.3%),AAImax为48±11(12例AAI>40,100%)。麻醉维持过程中,出现14次BIS>75,并发体动反应4次(28.5%),BIS反应时间较体动时间滞后(84±19)s;出现AAI>40者28次,并发体动者12次(42.8%),AAI反应时间较体动时间滞后(13±3)s。结论异丙酚麻醉下BIS、AAI反应时间较体动发生时间滞后,不能预测术中体动反应的发生。  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