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   245792篇
  免费   19630篇
  国内免费   8230篇
耳鼻咽喉   1810篇
儿科学   4310篇
妇产科学   2859篇
基础医学   36399篇
口腔科学   3951篇
临床医学   19205篇
内科学   46388篇
皮肤病学   3604篇
神经病学   17101篇
特种医学   5045篇
外国民族医学   56篇
外科学   16944篇
综合类   33482篇
现状与发展   20篇
一般理论   7篇
预防医学   13679篇
眼科学   2559篇
药学   35916篇
  84篇
中国医学   11317篇
肿瘤学   18916篇
  2024年   628篇
  2023年   4471篇
  2022年   9698篇
  2021年   12094篇
  2020年   9452篇
  2019年   7964篇
  2018年   7724篇
  2017年   7730篇
  2016年   7962篇
  2015年   9111篇
  2014年   15065篇
  2013年   16218篇
  2012年   14453篇
  2011年   16507篇
  2010年   13373篇
  2009年   13585篇
  2008年   13237篇
  2007年   12151篇
  2006年   10819篇
  2005年   9401篇
  2004年   7820篇
  2003年   6893篇
  2002年   5529篇
  2001年   4605篇
  2000年   3888篇
  1999年   3484篇
  1998年   3165篇
  1997年   2945篇
  1996年   2666篇
  1995年   2346篇
  1994年   2138篇
  1993年   1874篇
  1992年   1641篇
  1991年   1482篇
  1990年   1234篇
  1989年   1074篇
  1988年   1015篇
  1987年   859篇
  1986年   776篇
  1985年   1167篇
  1984年   1049篇
  1983年   722篇
  1982年   762篇
  1981年   600篇
  1980年   509篇
  1979年   414篇
  1978年   298篇
  1977年   244篇
  1976年   227篇
  1975年   147篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
91.
《Clinical neurophysiology》2020,131(1):213-224
ObjectiveSystematically review the abnormalities in event related potential (ERP) recorded in Rett Syndrome (RTT) patients and animals in search of translational biomarkers of deficits related to the particular neurophysiological processes of known genetic origin (MECP2 mutations).MethodsPubmed, ISI Web of Knowledge and BIORXIV were searched for the relevant articles according to PRISMA standards.ResultsERP components are generally delayed across all sensory modalities both in RTT patients and its animal model, while findings on ERPs amplitude strongly depend on stimulus properties and presentation rate. Studies on RTT animal models uncovered the abnormalities in the excitatory and inhibitory transmission as critical mechanisms underlying the ERPs changes, but showed that even similar ERP alterations in auditory and visual domains have a diverse neural basis. A range of novel approaches has been developed in animal studies bringing along the meaningful neurophysiological interpretation of ERP measures in RTT patients.ConclusionsWhile there is a clear evidence for sensory ERPs abnormalities in RTT, to further advance the field there is a need in a large-scale ERP studies with the functionally-relevant experimental paradigms.SignificanceThe review provides insights into domain-specific neural basis of the ERP abnormalities and promotes clinical application of the ERP measures as the non-invasive functional biomarkers of RTT pathophysiology.  相似文献   
92.
目的对附加钢板技术治疗股骨干髓内钉术后骨不连的历史、现状和进展进行综述。方法广泛查阅国内外关于附加钢板技术治疗股骨干髓内钉术后骨不连的临床研究文献,并进行综合分析。结果自 1997 年附加钢板技术已成功用于治疗股骨干髓内钉术后骨不连,根据原髓内钉是否失效,可分为保留原髓内钉和更换原髓内钉两类。该技术不仅适用于简单骨不连,还可用于合并严重畸形的复杂性骨不连。相比更换髓内钉、更换外侧钢板和双钢板技术,附加钢板技术手术创伤更小,骨折愈合时间更短,骨折愈合率更高,患者能更早重返社会和工作。然而,该技术也存在一些问题有待解决,包括双皮质螺钉固定困难、缺乏适合股骨干解剖型附加钢板以及缺乏术后功能和生活质量的评估研究。结论相比其他翻修固定方式,附加钢板技术能够获得更高的骨折愈合率和更好的临床预后。然而,术后患者能否在功能和生活质量方面进一步获益还有待证实。此外,还需要更高质量的临床对照研究深入证明其是否确实优于其他翻修固定方式。  相似文献   
93.
94.
95.
96.
The current coronavirus disease (COVID‐19) outbreak, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has raised the possibility of potential neurotropic properties of this virus. Indeed, neurological sequelae of SARS‐CoV‐2 infection have already been reported and highlight the relevance of considering the neurological impact of coronavirus (CoV) from a translational perspective. Animal models of SARS and Middle East respiratory syndrome, caused by structurally similar CoVs during the 2002 and 2012 epidemics, have provided valuable data on nervous system involvement by CoVs and the potential for central nervous system spread of SARS‐CoV‐2. One key finding that may unify these pathogens is that all require angiotensin‐converting enzyme 2 as a cell entry receptor. The CoV spike glycoprotein, by which SARS‐CoV‐2 binds to cell membranes, binds angiotensin‐converting enzyme 2 with a higher affinity compared with SARS‐CoV. The expression of this receptor in neurons and endothelial cells hints that SARS‐CoV‐2 may have higher neuroinvasive potential compared with previous CoVs. However, it remains to be determined how such invasiveness might contribute to respiratory failure or cause direct neurological damage. Both direct and indirect mechanisms may be of relevance. Clinical heterogeneity potentially driven by differential host immune‐mediated responses will require extensive investigation. Development of disease models to anticipate emerging neurological complications and to explore mechanisms of direct or immune‐mediated pathogenicity in the short and medium term is therefore of great importance. In this brief review, we describe the current knowledge from models of previous CoV infections and discuss their potential relevance to COVID‐19.  相似文献   
97.
《Value in health》2020,23(10):1340-1348
ObjectivesWe applied principles for conducting economic evaluations of factorial trials to a trial-based economic evaluation of a cluster-randomized 2 × 2 × 2 factorial trial. We assessed the cost-effectiveness of atorvastatin, omega-3 fish oil, and an action-planning leaflet, alone and in combination, from a UK National Health Service perspective.MethodsThe Atorvastatin in Factorial With Omega EE90 Risk Reduction in Diabetes (AFORRD) Trial randomized 800 patients with type 2 diabetes to atorvastatin, omega-3, or their respective placebos and randomized general practices to receive a leaflet-based action-planning intervention designed to improve compliance or standard care. The trial was conducted at 59 UK general practices. Sixteen-week outcomes for each trial participant were extrapolated for 70 years using the United Kingdom Prospective Diabetes Study Outcomes Model v2.01. We analyzed the trial as a 2 × 2 factorial trial (ignoring interactions between action-planning leaflet and medication), as a 2 × 2 × 2 factorial trial (considering all interactions), and ignoring all interactions.ResultsWe observed several qualitative interactions for costs and quality-adjusted life-years (QALYs) that changed treatment rankings. However, different approaches to analyzing the factorial design did not change the conclusions. There was a ≥99% chance that atorvastatin is cost-effective and omega-3 is not, at a £20 000/QALY threshold.ConclusionsAtorvastatin monotherapy was the most cost-effective combination of the 3 trial interventions at a £20 000/QALY threshold. Omega-3 fish oil was not cost-effective, while there was insufficient evidence to draw firm conclusions about action planning. Recently-developed methods for analyzing factorial trials and combining parameter and sampling uncertainty were extended to estimate cost-effectiveness acceptability curves within a 2x2x2 factorial design with model-based extrapolation.  相似文献   
98.
The aetiology of vitiligo has not been fully elucidated, and several hypotheses have been investigated; among them, the most explored assumes an autoimmune basis for the disease. Supporting this hypothesis is the frequent co-occurrence of autoimmune diseases with vitiligo. In addition, various genetic loci associated with vitiligo harbour key immune response genes. Our general hypothesis is that autoimmunity-associated genes participate in the control of vitiligo susceptibility. To investigate this hypothesis, we tested for association between vitiligo and genes CYP27B1, REL, TNFAIP3 and IL2/IL21, all previously related to autoimmune diseases associated with vitiligo. The study was performed using two independent population samples: a family-based discovery set (211 trios) and a replication set (131 cases/119 controls). Statistically significant association with vitiligo was detected between markers of the REL and IL2 gene in the family-based sample. Both association signals were concentrated among patients displaying autoimmune comorbidity and non-segmental vitiligo. Evidence for validation was detected for IL2 marker. Our findings suggest REL and IL2 as new vitiligo susceptibility genes and reinforce the hypothesis of a shared genetic mechanism controlling vitiligo and other autoimmune diseases.  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