共查询到19条相似文献，搜索用时 240 毫秒
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本文研究了科技文献副主题词的自动抽取问题,并对其在分面检索中的应用进行了探索。为实现副主题词的自动标引,本文提出了以标题作为抽取数据源、基于规则进行抽取的实现方法,并以图情领域文献进行了实验。结果显示,基于规则的抽取方法在召回率和准确率方面表现良好,均超过了90%;但仅以标题作为抽取数据源会导致召回率偏低,仅有49.9%的文献能抽取出副主题词。为探索副主题词在分面检索中的应用,本文以图情领域文献为例构建了原型系统,从使用效果来,副主题词作为独立的检索点价值不大,但和其他检索点配合使用则可以更贴切地表达用户需求,作为分面则能在帮助用户进行探索式检索以及结果筛选方面发挥重要作用。本研究的局限性包括仅采用标题作为副主题词抽取数据源,导致召回率不高;在副主题词抽取时未考虑同时抽取相应的主题词等。 相似文献
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副主题词是指主题词所论述的重点课题的自然范畴或者通常发生的某一方面,对主题词限定的一类词汇。副主题词本身涉及医学研究的特定范畴,通过对副主题词频率的统计分析可以揭示医学研究的热点与方向。本文采用基本检索的方式,检索了近年来在中国生物医学文献数据库（CBM）所标引的文献,从中抽取3000篇文献,对其中的副主题词出现的频次进行统计,并对统计结果以图表的形式进行了分析。希望信息用户能根据这些分析更加了解在学科上医学文献的研究热点与特色,以期待更好的为临床及科学研究服务。 相似文献
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检索了MEDLINE光盘数据库1991—2009年收录的纳米技术对环境和人类健康影响的文献,利用文献计量学方法对其发表时间、国家、类型、期刊种类、主题词、副主题词等的分布进行了统计分析,旨在为科研人员提供参考。 相似文献
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本文结合工作实践,对《中国分类主题词表》第二版及电子版使用中一些新增主题词、删除和修订主题词使用中的具体问题进行了分析、探讨。 相似文献
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利用关联规则对医学文本数据库进行知识抽取的尝试*——以四种抗肿瘤药为例 总被引：2，自引：0，他引：2
利用关联规则算法，对PubMed数据库中的4种抗肿瘤药物主题词和副主题词组配模式进行分析，并以文献和教科书标准，抽取出与这四类药有关的、有效的语义关系搭配模式，从而为文献检索和建立知识库提供依据。 相似文献
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简要介绍当前国内外副主题词自动组配的研究现状,提出适用于中文生物医学文献处理的基于拼图-统计学习相结合的副主题词自动组配实现方法,详细阐述分析该混合策略方法的实现机制及实现效果,并指出后续的改进建议。 相似文献
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文献数据库中书目信息共现挖掘系统的开发 总被引：9，自引：0，他引：9
针对权威的生物医学数据库和引文索引数据,介绍一个基于文献数据库中书目信息共现关系进行文本挖掘的系统。该系统具有基本的文献计量学分析功能,并对相应的结果进行可视化表达;对高频主题词、高产作者和高被引论文和高被引作者进行共现分析,据此进行聚类分析和关联分析,获得有关的研究主题聚类和主题词/副主题词关联规则、合著聚类分析、高被引论文同被引聚类分析和高被引作者同被引聚类分析的结果和可视化表达。其中对关联规则的分析可以发现主题词之间的潜在语义规则,其他的文献计量学指标和共现分析结果可以用于科学计量学的分析。 相似文献
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王建春 《信息管理(上海)》2008,21(6)
本文介绍了主题词应用的概念要领、基本常识,明确了主题词标引的性质、特钲、方法和步骤,指出了正确使用主题词,标引规范词,对实现军用公文以及各类文献信息资源共享的作用。 相似文献
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急性白血病相关基因的文本挖掘分析 总被引：2，自引：0，他引：2
从PubMed检索1966年到2005年9月6日间白血病与基因关系的相关文献3 529篇.经编程处理生成主题词词篇矩阵并进行聚类.通过聚类树图可将所提取的主题词/副主题词分成13类,经对比原始文献进行验证,全部29种基因中只与ALL相关的有3种, 占10.34%;只与AML相关的有8种,占27.59%.特异的可用于鉴别ALL和AML的基因有11种,占37.93%.通过主题词的共现关系进行聚类可以基本实现发现基因与疾病之间的联系,但该方法所获得的相关基因较少,不利于对疾病与基因关系的全面了解. 相似文献
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Indexing consistency in MEDLINE 总被引：3，自引：0，他引：3
The quality of indexing of periodicals in a bibliographic data base cannot be measured directly, as there is no one "correct" way to index an item. However, consistency can be used to measure the reliability of indexing. To measure consistency in MEDLINE, 760 twice-indexed articles from 42 periodical issues were identified in the data base, and their indexing compared. Consistency, expressed as a percentage, was measured using Hooper's equation. Overall, checktags had the highest consistency. Medical Subject Headings (MeSH) and subheadings were applied more consistently to central concepts than to peripheral points. When subheadings were added to a main heading, consistency was lowered. "Floating" subheadings were more consistent than were attached subheadings. Indexing consistency was not affected by journal indexing priority, language, or length of the article. Terms from MeSH Tree Structure categories A, B, and D appeared more often than expected in the high-consistency articles; whereas terms from categories E, F, H, and N appeared more often than expected in the low-consistency articles. MEDLINE, with its excellent controlled vocabulary, exemplary quality control, and highly trained indexers, probably represents the state of the art in manually indexed data bases. 相似文献
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《Medical reference services quarterly》2013,32(3):29-46
Through casual observations, formal consultations, and educational sessions, the authors have identified various indexing features of the National Library of Medicine's Medical Subject Headings (MeSH) that pose challenges to end users while attempting to obtain relevant retrieval when searching MEDUNE. These problematic features include the use of Explodes, Tree structures, subheadings, Text Word vs. subject heading searching, and central concept searching. End-user search software is becoming more sophisticated with an increasing number of choices offered for search strategy fomalation. Methods of instruction to orient the end user to these systems will also have to become more detailed. A review of the literature, that discusses end-user problems with using MEDLINE and MeSH, is included. 相似文献
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Through casual observations, formal consultations, and educational sessions, the authors have identified various indexing features of the National Library of Medicine's Medical Subject Headings (MeSH) that pose challenges to end users while attempting to obtain relevant retrieval when searching MEDLINE. These problematic features include the use of Explodes, Tree structures, subheadings, Text Word vs. subject heading searching, and central concept searching. End-user search software is becoming more sophisticated with an increasing number of choices offered for search strategy formulation. Methods of instruction to orient the end user to these systems will also have to become more detailed. A review of the literature, that discusses end-user problems with using MEDLINE and MeSH, is included. 相似文献
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Bronson RJ 《Medical reference services quarterly》1994,13(1):73-80
Locating notes about MeSH subheadings can be one of the most difficult aspects of MEDLINE searching. When used with Medical Subject Headings (MeSH), subheadings serve to limit or define the focus of a heading. National Library of Medicine (NLM) indexers, staff members who enter the MeSH indexing into the database, use subheadings freely. They do follow indexing conventions and savy searchers need to be aware of how to obtain basic subheading information to assist in search formulation. There are a number of methods which may be used in order to view subheading use notes. This column will provide an overview of some alternatives to locating such information. 相似文献
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Golder S McIntosh HM Duffy S Glanville J;Centre for Reviews Dissemination UK Cochrane Centre Search Filters Design Group 《Health information and libraries journal》2006,23(1):3-12
OBJECTIVE: This study aimed to assess the performance, in terms of sensitivity and precision, of different approaches to searching MEDLINE and EMBASE to identify studies of adverse effects. METHODS: Five approaches to searching for adverse effects evidence were identified: approach 1, using specified adverse effects; approach 2, using subheadings/qualifiers; approach 3, using text words; approach 4, using indexing terms; approach 5, searching for specific study designs. The sensitivity and precision of these five approaches, and combinations of these approaches, were compared in a case study using a systematic review of the adverse effects of seven anti-epileptic drugs. RESULTS: The most sensitive search strategy in MEDLINE (97.0%) required a combination of terms for specified adverse effects, floating subheadings, and text words for 'adverse effects'. In EMBASE, a combination of terms for specified adverse effects and text words for 'adverse effects' provided the most sensitive search strategy (98.6%). Both these search strategies yielded low precision (2.8%). CONCLUSIONS: A highly sensitive search in either database requires a combination of approaches, and has low precision. This suggests that better reporting and indexing of adverse effects is required and that an effective generic search filter may not yet be feasible. 相似文献
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朱康玲 《中华医学图书馆杂志》2011,(6):61-63
从课程目标重新定位、调整教学大纲和教学理念、编制统一教材、将数据库共同点概括纳入绪论、将多数检索工具及数据库的相同或相似的检索途径、文献下载方式在绪论中总结概括等方面,论述了网络环境下医学文献检索课教学模式的改革,提出了增设信息分析和主题标引章节等教材内容及采取启发式、互动式、分层次教学方式。 相似文献
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中文期刊文献通用词标引分析 总被引：1，自引：0，他引：1
通用因素是文献主题的构成因素之一，对主体因素起细分作用。通用词是指那些在专业领域没有独立检索意义的泛指词。在中文期刊文献标引的过程中，通用词的使用对其标引结果产生着重要的影响。文章讨论了通用词标引的一般规则，并以《中国期刊网》中的文献为例，进行抽样统计和实例分析，归纳了通用词标引的错误现象及其原因，并对期刊文献的通用词标引提出了几点改进意见。 相似文献