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   139984篇
  免费   12361篇
  国内免费   4074篇
耳鼻咽喉   860篇
儿科学   3581篇
妇产科学   1569篇
基础医学   11181篇
口腔科学   1018篇
临床医学   21809篇
内科学   24219篇
皮肤病学   918篇
神经病学   7855篇
特种医学   5417篇
外国民族医学   6篇
外科学   12259篇
综合类   26397篇
现状与发展   9篇
预防医学   9291篇
眼科学   1792篇
药学   13603篇
  178篇
中国医学   11385篇
肿瘤学   3072篇
  2024年   176篇
  2023年   2122篇
  2022年   3130篇
  2021年   5766篇
  2020年   5958篇
  2019年   4775篇
  2018年   4488篇
  2017年   5115篇
  2016年   5215篇
  2015年   4862篇
  2014年   9149篇
  2013年   9522篇
  2012年   7929篇
  2011年   8384篇
  2010年   6808篇
  2009年   6240篇
  2008年   6388篇
  2007年   6777篇
  2006年   6088篇
  2005年   5380篇
  2004年   4599篇
  2003年   4130篇
  2002年   3567篇
  2001年   3393篇
  2000年   2746篇
  1999年   2365篇
  1998年   2006篇
  1997年   2007篇
  1996年   1653篇
  1995年   1779篇
  1994年   1637篇
  1993年   1251篇
  1992年   1297篇
  1991年   1114篇
  1990年   901篇
  1989年   829篇
  1988年   808篇
  1987年   686篇
  1986年   609篇
  1985年   799篇
  1984年   707篇
  1983年   450篇
  1982年   601篇
  1981年   435篇
  1980年   369篇
  1979年   305篇
  1978年   279篇
  1977年   207篇
  1976年   205篇
  1975年   109篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
61.
62.
63.
Transfusion emergency preparedness is increasingly being recognized as an important element in the healthcare response to mass casualty events (MCE). Planning should be designed to support an integrated response between the blood services and hospitals. The lessons identified from the Manchester Arena bombing in 2017 and recent incidents in London have led to new guidance. Demand planning has been informed by the global experience of civilian MCEs and the changing trends in trauma care. Past evidence suggests that only a modest number of hospitalized patients following MCEs require transfusion. The mean blood use per patient admitted is consistently calculated at 2–3 red cell units. Most blood is used within the first 6 h. However, a small number of critically injured with multi‐trauma may require massive transfusion and ongoing support. Many blood services have reported meeting the initial overall demand for blood from stock. However, universal components may be in short supply. The demand can be managed by pre‐agreed substitutions. Early transfusion triage enables the best use of hospital laboratory and blood service support. Careful communication with donor communities is essential to manage a controlled replenishment of stocks. Future challenges for the transfusion community include the trend towards lower red cell stock holdings and the changing trends in weapon use and tactics. A standardized approach to transfusion data collection is required to support future planning. The transfusion community is encouraged to plan for MCEs, contribute to ‘after action reviews’ and work together for safe and sustainable transfusion support.  相似文献   
64.
65.
66.
Background: Intensive blood pressure (BP) lowering may offer protective effects against major adverse cardiac event (MACE) but is also associated with a greater risk of a serious adverse event (SAE). The risk-benefit profile of intensive versus standard BP control has not been comprehensively assessed. Methods: Four studies were identified from a systematic literature search for randomized controlled trials comparing intensive versus standard BP lowering that reported both MACE and SAE endpoints. A previously described statistical approach was applied to characterize the efficacy-safety tradeoff of BP control. The bivariate outcome was computed to quantitatively assess the net clinical benefit (NCB) of intensive BP lowering as compared to standard treatment, with positive values indicating increased risks and negative values indicating decreased risks. Results: Data from the SPRINT trial demonstrated that intensive strategy was superior in MACE but inferior in SAE, thereby eroding the NCB (bivariate outcome: 0.33% [?0.50% to 1.21%]). Intensive strategy from the SPS3 trial fulfilled non-inferiority in both MACE and SAE but did not reach a favorable NCB (?1.31% [?2.25% to 0.01%]). The ACCORD trial suggested that intensive strategy was non-inferior in MACE but inferior in SAE (?0.19% [?0.79% to 1.37%]). Results from the VALISH trial were inconclusive for SAE but suggested non-inferiority in MACE (?1.19% [?3.24% to 0.68%]). Conclusions: Compared to the standard blood pressure target, pooled data from randomized controlled trials suggest that intensive strategy did not achieve a net clinical benefit when weighing the benefit of MACE reduction against the risk of SAE under the bivariate framework.Abbreviations: Blood pressure (BP), diastolic blood pressure (DBP), major adverse cardiac event (MACE), net clinical benefit (NCB), serious adverse event (SAE), systolic blood pressure (SBP).  相似文献   
67.
68.
69.
《Clinical neurophysiology》2019,130(5):727-738
ObjectiveFunctional processes in the brain are segregated in both the spatial and spectral domain. Motivated by findings reported at the cortical level in healthy participants we test the hypothesis in the basal ganglia of Parkinson’s disease patients that lower frequency beta band activity relates to motor circuits associated with the upper limb and higher beta frequencies with lower limb movements.MethodsWe recorded local field potentials (LFPs) from the subthalamic nucleus using segmented “directional” DBS leads, during which patients performed repetitive upper and lower limb movements. Movement-related spectral changes in the beta and gamma frequency-ranges and their spatial distributions were compared between limbs.ResultsWe found that the beta desynchronization during leg movements is characterised by a strikingly greater involvement of higher beta frequencies (24–31 Hz), regardless of whether this was contralateral or ipsilateral to the limb moved. The spatial distribution of limb-specific movement-related changes was evident at higher gamma frequencies.ConclusionLimb processing in the basal ganglia is differentially organised in the spectral and spatial domain and can be captured by directional DBS leads.SignificanceThese findings may help to refine the use of the subthalamic LFPs as a control signal for adaptive DBS and neuroprosthetic devices.  相似文献   
70.
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