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   641篇
  免费   208篇
  国内免费   14篇
耳鼻咽喉   1篇
儿科学   3篇
基础医学   96篇
口腔科学   6篇
临床医学   51篇
内科学   80篇
皮肤病学   2篇
神经病学   201篇
特种医学   51篇
外科学   22篇
综合类   141篇
预防医学   93篇
眼科学   2篇
药学   54篇
中国医学   53篇
肿瘤学   7篇
  2024年   7篇
  2023年   40篇
  2022年   37篇
  2021年   70篇
  2020年   55篇
  2019年   55篇
  2018年   45篇
  2017年   49篇
  2016年   36篇
  2015年   50篇
  2014年   59篇
  2013年   40篇
  2012年   39篇
  2011年   30篇
  2010年   33篇
  2009年   28篇
  2008年   34篇
  2007年   27篇
  2006年   16篇
  2005年   20篇
  2004年   12篇
  2003年   12篇
  2002年   4篇
  2001年   10篇
  2000年   10篇
  1999年   4篇
  1998年   4篇
  1997年   4篇
  1996年   4篇
  1995年   6篇
  1994年   5篇
  1993年   2篇
  1992年   4篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1984年   4篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
排序方式: 共有863条查询结果,搜索用时 109 毫秒
1.
[摘要] 目的 对发热伴血小板减少综合征(severe fever with thrombocytopenia syndrome, SFTS)的相关文献进行文献计量学和可视化分析,探寻近年来的研究现状、热点及趋势,为临床治疗和基础研究提供参考。方法?以Web of Science(WOS)核心合集和中国知网(China national knowledge infrastructure, CNKI)数据库为文献来源,检索2011年1月1日—2021年12月31日有关SFTS的文献,导入CiteSpace.5.7.R2软件,以国家、作者、文献共被引、关键词为节点进行可视化分析,并绘制相关图谱。结果?在WOS核心合集共检索到797篇文献,在CNKI数据库共检索到714篇文献。相关领域发文量总体呈上升趋势,中国发文量居首位,美国和日本之间机构合作密切。研究热点集中在发病机制、抗体、特异性治疗等领域。非结构蛋白、临床预后、血小板减少、SFTS感染的靶细胞等将是未来的研究重点。结论?国内外关于SFTS的研究逐渐成熟,新型布尼亚病毒、免疫功能、预后是研究重点,但是对SFTS发病机制和病毒受体尚不清楚,仍须进一步探索。  相似文献   
2.
[摘要] 目的 对发热伴血小板减少综合征(severe fever with thrombocytopenia syndrome, SFTS)的相关文献进行文献计量学和可视化分析,探寻近年来的研究现状、热点及趋势,为临床治疗和基础研究提供参考。方法?以Web of Science(WOS)核心合集和中国知网(China national knowledge infrastructure, CNKI)数据库为文献来源,检索2011年1月1日—2021年12月31日有关SFTS的文献,导入CiteSpace.5.7.R2软件,以国家、作者、文献共被引、关键词为节点进行可视化分析,并绘制相关图谱。结果?在WOS核心合集共检索到797篇文献,在CNKI数据库共检索到714篇文献。相关领域发文量总体呈上升趋势,中国发文量居首位,美国和日本之间机构合作密切。研究热点集中在发病机制、抗体、特异性治疗等领域。非结构蛋白、临床预后、血小板减少、SFTS感染的靶细胞等将是未来的研究重点。结论?国内外关于SFTS的研究逐渐成熟,新型布尼亚病毒、免疫功能、预后是研究重点,但是对SFTS发病机制和病毒受体尚不清楚,仍须进一步探索。  相似文献   
3.
Partial differential equations (PDEs) play a dominant role in the mathematical modeling of many complex dynamical processes. Solving these PDEs often requires prohibitively high computational costs, especially when multiple evaluations must be made for different parameters or conditions. After training, neural operators can provide PDEs solutions significantly faster than traditional PDE solvers. In this work, invariance properties and computational complexity of two neural operators are examined for transport PDE of a scalar quantity. Neural operator based on graph kernel network (GKN) operates on graph-structured data to incorporate nonlocal dependencies. Here we propose a modified formulation of GKN to achieve frame invariance. Vector cloud neural network (VCNN) is an alternate neural operator with embedded frame invariance which operates on point cloud data. GKN-based neural operator demonstrates slightly better predictive performance compared to VCNN. However, GKN requires an excessively high computational cost that increases quadratically with the increasing number of discretized objects as compared to a linear increase for VCNN.  相似文献   
4.
科学合理地种植中草药是解决中药资源紧缺、保障中药质量的根本方法。中草药品质受种子种苗、种植措施、土壤状况等多种因素影响,各影响因素对中草药品质产生不同的作用,但迄今为止并没有通过调控中草药种植因素分析中药材品质的模型和方法。因此,本研究通过文献调研结合专家种植经验,综合分析影响中草药种植指标的复杂因素,以提高中药材品质为目标,基于图数据库的方法构建影响不同中草药种植品质的知识图谱,探讨中草药种植因素与指标之间的关系,通过调节影响中药材品质的因素,为中草药种植以及提高中药品质提供依据。  相似文献   
5.
名医经验传承是中医药文化传承和发展的重要内容。本文结合当前名医经验传承研究的基本现状以及名医学术经验整理与深度传承发展的核心需求,提出基于知识图谱的名医经验传承模式研究构想。利用知识图谱在多维度知识及海量信息网络整合方面的优势,从名医学术源流整理,学术思想挖掘及临床经验整理等多个角度出发,探讨知识图谱构建和挖掘分析的研究思路。通过多主题、结构化的知识图谱构建,探索名医经验传承系统化、规范化建设的新思路。  相似文献   
6.
Jet lag is commonly experienced when travelers cross multiple time zones, leaving the wake–sleep cycle and intrinsic biological “clocks” out of synchrony with the current environment. The effect of jet lag on intrinsic cortical function remains unclear. Twenty‐two healthy individuals experiencing west‐to‐east jet lag flight were recruited. Brain structural and functional magnetic resonance studies, as well as psychological and neurohormonal tests, were carried out when participants returned from travel over six time zones and 50 days later when their jet lag symptoms had resolved. During jet lag, the functional brain network exhibited a small‐world topology that was shifted toward regularity. Alterations during jet lag relative to recovery included decreased basal ganglia‐thalamocortical network connections and increased functional connectivity between the medial temporal lobe subsystem and medial visual cortex. The lower melatonin and higher thyroid hormone levels during jet lag showed the same trend as brain activity in the right lingual gyrus. Although there was no significant difference between cortisol measurements during and after jet lag, cortisol levels were associated with temporal lobe activity in the jet lag condition. Brain and neuroendocrine changes during jet lag were related to jet lag symptoms. Further prospective studies are needed to explore the time course over which jet lag acts on the human brain.  相似文献   
7.
Graph theory and network modelling have been previously applied to characterize motor network structural topology in multiple sclerosis (MS). However, between‐group differences disclosed by graph analysis might be primarily driven by discrepancy in density, which is likely to be reduced in pathologic conditions as a consequence of macroscopic damage and fibre loss that may result in less streamlines properly traced. In this work, we employed the convex optimization modelling for microstructure informed tractography (COMMIT) framework, which, given a tractogram, estimates the actual contribution (or weight) of each streamline in order to optimally explain the diffusion magnetic resonance imaging signal, filtering out those that are implausible or not necessary. Then, we analysed the topology of this ‘COMMIT‐weighted sensory‐motor network’ in MS accounting for network density. By comparing with standard connectivity analysis, we also tested if abnormalities in network topology are still identifiable when focusing on more ‘quantitative’ network properties. We found that topology differences identified with standard tractography in MS seem to be mainly driven by density, which, in turn, is strongly influenced by the presence of lesions. We were able to identify a significant difference in density but also in network global and local properties when accounting for density discrepancy. Therefore, we believe that COMMIT may help characterize the structural organization in pathological conditions, allowing a fair comparison of connectomes which considers discrepancies in network density. Moreover, discrepancy‐corrected network properties are clinically meaningful and may help guide prognosis assessment and treatment choice.  相似文献   
8.
目的 以“中医体质辨识”为主题开展系统的可视化分析,探索中医体质辨识领域的发展现状、研究热点、发展趋势,为后续研究提供借鉴。方法 以中国知网(CNKI)数据库为数据源检索相关文献,并将所得数据文件导入CiteSpace软件,对作者、机构和关键词进行共现分析并得到相关知识图谱。结果 共纳入1099篇文献,通过CiteSpace共现分析找到中医体质辨识领域研究的高产机构、具有代表性的研究者以及高频关键词。研究发现各个研究者及机构缺乏沟通合作,研究热点主题有体质研究、治未病、健康管理、与现代生物医学相结合。结论 中医体质辨识领域的研究逐年增加,知识图谱揭示了中医体质辨识在健康管理、与现代生物医学相结合将是未来的研究趋势。  相似文献   
9.
Large quantities of data are now available to medical researchers; however, observational studies are plagued by bias and confounding. Additionally, much of this research only speculates on variable associations, leaving prospective randomized clinical trials as the sole purveyors of claims about causal relations between variables. There has been a growing movement of causal inference that uses new techniques to investigate causality using observational data. These techniques include the implementation of directed acyclic graphs, which allow researchers to explicitly and reproducibly define the causal relationships between study variables, thus making statistical analysis more robust. Directed acyclic graphs further allow researchers to identify confounding and other sources of bias and to discover causal effects among complex networks of variables. This review aims to introduce these techniques to the general urology and urologic oncology research communities in order to provide a basic understanding of causal inference and analysis and call for integration of these practices more generally in research methodology.  相似文献   
10.
目的 构建个性化知识图谱技术和定性访谈法结合,进一步挖掘张忠德教授辨治间质性肺疾病临证特征与用药规律。方法 采用回顾性分析,系统收集张忠德教授广东省中医院门诊2010年8月至2020年8月治疗间质性肺疾病病历,按照诊断标准、纳入标准、排除标准,严格筛选后,通过广东省中医院大数据挖掘团队中医药大数据智能处理与知识服务系统进行数据挖掘分析,并通过多元化视觉定性访谈法,将定量与定性分析有效结合。结果 共筛选出347首方,共141味药物,常用药物频次 ≥ 84次的药物有10味,其中党参、麦芽、黄芪、紫菀、白术等为核心用药,通过症状与药物推理知识地图显示,党参、炒麦芽、黄芪、大枣、太子参、山萸肉、巴戟天等为主要治疗用药;临证遣方用药知识关联分析,得知咳嗽、耳鸣、心悸、水肿、头痛、胸闷、恶寒等为多见,针对咳嗽,首选紫苏子、橘红、桂枝等温肺降气通阳之品等;频繁聚集显示,常用药对炒麦芽-炒白术、黄芪-党参、黄精-菟丝子、前胡-紫菀、炙枇杷叶-浙贝母等;聚类分析结果得到4组关系密切的聚类新药物组合;以脾为中轴,肺肾共扶为主的“平调五脏论”,分期阶梯辨治间质性肺疾病。结论 张忠德教授认为间质性肺疾病,虚实夹杂为多见,应从肺、脾、肾着手,采用平调五脏论分期阶梯辨治,用药配伍精简,以和为贵,以平为期。  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