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   4294332篇
  免费   349980篇
  国内免费   14481篇
耳鼻咽喉   60185篇
儿科学   139106篇
妇产科学   114234篇
基础医学   656429篇
口腔科学   117911篇
临床医学   392426篇
内科学   774952篇
皮肤病学   108000篇
神经病学   362879篇
特种医学   169064篇
外国民族医学   753篇
外科学   652212篇
综合类   120970篇
现状与发展   24篇
一般理论   2615篇
预防医学   353489篇
眼科学   100476篇
药学   306202篇
  21篇
中国医学   11541篇
肿瘤学   215304篇
  2021年   50491篇
  2020年   35810篇
  2019年   58786篇
  2018年   74407篇
  2017年   56695篇
  2016年   62832篇
  2015年   75772篇
  2014年   110141篇
  2013年   175868篇
  2012年   124296篇
  2011年   129001篇
  2010年   125970篇
  2009年   127751篇
  2008年   115265篇
  2007年   122526篇
  2006年   131352篇
  2005年   125484篇
  2004年   126785篇
  2003年   116724篇
  2002年   105612篇
  2001年   166342篇
  2000年   160993篇
  1999年   146368篇
  1998年   65948篇
  1997年   61854篇
  1996年   59784篇
  1995年   60550篇
  1994年   54592篇
  1993年   50578篇
  1992年   106247篇
  1991年   101314篇
  1990年   97106篇
  1989年   94647篇
  1988年   86907篇
  1987年   85141篇
  1986年   80030篇
  1985年   78204篇
  1984年   65109篇
  1983年   57789篇
  1982年   46738篇
  1981年   43422篇
  1980年   40615篇
  1979年   54756篇
  1978年   44431篇
  1977年   39561篇
  1976年   36470篇
  1975年   36502篇
  1974年   39392篇
  1973年   37571篇
  1972年   35280篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
This paper examines the propagation of COVID-19 across the Spanish provinces and assesses the effectiveness of the Spanish lockdown of the population implemented on March 14, 2020 in order to battle this pandemic. To achieve these objectives, a standard spatial econometric model used in economics is adapted to resemble the popular reproduction models employed in the epidemiological literature. In addition, we introduce a counterfactual exercise that allows us to examine the Gross domestic product (GDP) gains of bringing forward the date of the Spanish Lockdown. We find that the number of COVID-19 cases would have been reduced by 70.4% in the absence of spatial propagation between the Spanish provinces. We also determine that the lockdown prevented the propagation of the virus within and between provinces. As such, the Spanish lockdown reduced the number of potential COVID-19 cases by 82.8%. However, the number of coronavirus cases would have been reduced by an additional 11.6% if the lockdown had been brought forward to March 7, 2020. Finally, an earlier lockdown would have saved approximately 26,900,000,000 euros.  相似文献   
93.
94.
95.
Brandt  L.  Albert  S.  Brandt  K. L. 《Der Anaesthesist》2022,71(11):858-864
Die Anaesthesiologie - Als Meralgia paraesthetica (MP) bezeichnet man eine zu den neurologischen Engpasssyndromen zählende Schädigung des aus dem Plexus lumbalis entspringenden sensiblen...  相似文献   
96.
Delirium is one of the most commonly occurring postoperative complications in older adults. It occurs due to the vulnerability of cerebral functioning to pathophysiological stressors. Identification of those at increased risk of developing delirium early in the surgical pathway provides an opportunity for modification of predisposing and precipitating risk factors and effective shared decision-making. No single delirium prediction tool is used widely in surgical settings. Multi-component interventions to prevent delirium involve structured risk factor modification supported by geriatrician input; these are clinically efficacious and cost effective. Barriers to the widespread implementation of such complex interventions exist, resulting in an ‘implementation gap’. There is a lack of evidence for pharmacological prophylaxis for the prevention of delirium. Current evidence suggests that avoidance of peri-operative benzodiazepines, careful titration of anaesthetic depth guided by processed electroencephalogram monitoring and treatment of pain are the most effective strategies to minimise the risk of delirium. Addressing postoperative delirium requires a collaborative, whole pathway approach, beginning with the early identification of those patients who are at risk. The research agenda should continue to examine the potential for pharmacological prophylaxis to prevent delirium while also addressing how successful models of delirium prevention can be translated from one setting to another, underpinned by implementation science methodology.  相似文献   
97.
98.
PurposeUnderstanding the value of genetic screening and testing for monogenic disorders requires high-quality, methodologically robust economic evaluations. This systematic review sought to assess the methodological quality among such studies and examined opportunities for improvement.MethodsWe searched PubMed, Cochrane, Embase, and Web of Science for economic evaluations of genetic screening/testing (2013-2019). Methodological rigor and adherence to best practices were systematically assessed using the British Medical Journal checklist.ResultsAcross the 47 identified studies, there were substantial variations in modeling approaches, reporting detail, and sophistication. Models ranged from simple decision trees to individual-level microsimulations that compared between 2 and >20 alternative interventions. Many studies failed to report sufficient detail to enable replication or did not justify modeling assumptions, especially for costing methods and utility values. Meta-analyses, systematic reviews, or calibration were rarely used to derive parameter estimates. Nearly all studies conducted some sensitivity analysis, and more sophisticated studies implemented probabilistic sensitivity/uncertainty analysis, threshold analysis, and value of information analysis.ConclusionWe describe a heterogeneous body of work and present recommendations and exemplar studies across the methodological domains of (1) perspective, scope, and parameter selection; (2) use of uncertainty/sensitivity analyses; and (3) reporting transparency for improvement in the economic evaluation of genetic screening/testing.  相似文献   
99.
100.
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