共查询到20条相似文献，搜索用时 46 毫秒
1.
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
2.
3.
概念分面组配型自动分类系统 总被引：1，自引：1，他引：0
１选择自动分类模式的基本思路当前，迫切需要符合下列要求的一种自动分类模式：（１）能够较快付诸实用；（２）有较高的检索效率，特别是检准率；（３）为了保证较高的检索效率，可适当采用人工辅助抽词。从自动分类研究的进展情况看，要达到（１）（２）点要求而完全不用人工辅助抽词（准确地抽取文献主题的核心词），目前是不可能做到的。也就是说，（１）（２）（３）点都是必要的；（４）充分利用系统资源，提供更多检索功能。概念分面组配型自动分类模式比较符合以上要求。这种模式可简略表述如下：以文献题名作为主要抽词对象；适当… 相似文献
4.
适用于隐含主题抽取的K最近邻关键词自动抽取 总被引：1，自引：0，他引：1
众所周知,K最近邻方法作为机器学习领域的一个经典的方法,在很多领域都有出色的表现.本文利用K最近邻方法的思想,提出了一种基于K最近邻的关键词自动抽取方法.现有的关键词抽取技术仅仅是对正文词汇的抽取,不能抽取隐含主题.隐含主题的抽取是关键词自动抽取技术的难点,但是该方法可以有效抽取隐含主题.该方法首先对数据进行预处理,使用向量空间模型将文本表述为数学化语言;然后,以人工标注关键词的文献数据作为训练集,使用K最近邻方法构建新文献的关键词候选集;最后,根据关键词本身的特点对候选关键词做了有效的后处理.实验表明,该方法不仅可以提高关键词抽取的准确率和召回率,还可以有效抽取文章的隐含主题. 相似文献
5.
提出一种新的政务本体术语自动抽取的方法。首先通过中文分词技术和单字合并法提取政务文本中的词作为候选术语;通过C-value求解法和TF-IDF算法对候选术语进行过滤抽取,从而实现政务领域术语的自动抽取。通过实验比较,发现该方法在不影响领域术语抽取召回率的同时可以提高抽取术语的正确率。 相似文献
6.
专利术语抽取是专利文献信息抽取领域的一项重要任务,有助于专利领域词表的构建,有利于中文分词、句法分析、语法分析等工作的进行。文章通过分析专利术语的特点并制定相应的语料标注规则进行人工标注,采用条件随机场（conditional random fields,CRFs）对标注后的数据进行训练和测试,实现了通信领域的术语抽取。标注方法采用基于字的序列标注,精确率、召回率和F值分别达到80.9%、75.6%、78.2%,优于将词和词性等信息作为特征的方法,表明所提出的专利术语抽取方法是有效的。 相似文献
7.
在向文献数据库发送检索提问后,用户检索到的往往是数量众多且线性排列的文献记录,如何进一步分类这些文献记录以方便用户使用是信息检索领域的重要课题之一。本文以一个比较狭小的主题(脊髓损伤)为文献查询提问,探索利用原数据库中提供的论文主题相似性信息对检索到的文献记录进行聚类的方法,并对每个类别赋予类别标签。本文①利用生物医学权威文献数据库Medline,分别检索PubMed中有关脊髓损伤的部分文献(源文献),实际操作中我们抽取近两年发表的有关脊髓损伤的1906篇文献中前50篇;②利用PubMed中的相关文献功能分别检索出源文献的相关文献(共5108篇),筛选出频次较高的相关文献(出现频次大于或等于5次,共31篇);③形成源文献和相关文献的关联矩阵,根据该矩阵对来源文献进行聚类分析;④分别采用人工分析和主题词的向量空间模型算法提取各类的文献内容或类标签,初步评价分类结果的正确性。经过基于相似性的聚类分析,可以将脊髓损伤的源文献分为3个大类,对比人工分析和主题词向量空间模型方法对来源文献的内容提取,二者基本相符。就本文研究涉及的主题而言,利用文献数据库中提供的论文相关性信息对检索结果进行再次分类的方法是可行的。 相似文献
8.
分众分类标签的语义模糊性和标签无序性使得检索效率越来越低,为准确定位标签语义,旨在研究一种新的方法,从主题词表的词间关系判断标签间的语义关系。以《中国分类主题词表》教育类主题词搜索Delicious网站得到的相关标签作为数据源,分析标签与主题词的重叠度,选择《中国分类主题词表》和ERIC在线教育词表作为标签的语义关系抽取工具,认为相关标签集中语义关系较为丰富。 相似文献
9.
文章对图情领域有关用户研究的文献进行了分析,给出了面向使用的用户研究热点内容及主流研究方法,引入分面分类的思想深入剖析用户研究主要方法,并给出了建议。 相似文献
10.
分类法主题法一体化自动标引系统的基本原理和方法 总被引：7，自引：0，他引：7
本文阐述基于文献题名的自动标引系统的原理和方法，该系统是分类法主题法一体化的。文中说明了依据文献题名对文献进行分类和主题标引的可行性、从题名中自动轴词、以体系分类法为基础的自动分类用分类词表、自动分类规则及以分面分类法为基础的文献自动分类、自由体系自动分类、半自动抽词、检索系统的分类法主题法一体化检索功能保证检索系统质量的关键因素等问题。 相似文献
11.
《Slavic & East European Information Resources》2013,14(1-2):123-143
ABSTRACT The article examines the most important periodicals of ethnic minorities in Poland. After 1989, many ethnic groups (e.g., Germans and Romanies) were allowed to publish journals and newspapers for the first time since the end of World War II. The publications examined show the rich cultural life of the various ethnic groups as well as their current status in Poland. In addition to popular titles, some scholarly publications are also discussed. 相似文献
12.
Jon C. Giullian 《Slavic & East European Information Resources》2013,14(3):278-284
The author answers a reference question on bibliographic sources for the Ukrainian periodical press 1840–1850. Helpful publications include bibliographies, guides, and library catalogs. These potentially make mention of revolutionary developments in Hungary (such as the Twelve Points paragraph of the Demands of the Hungarian Nation in March 1848, the subsequent April Laws, and Hungary's declaration of independence in April 1949), and elsewhere in the Hapsburg Empire. 相似文献
13.
Most studies of collection development mask inadequate theoretical underpinnings with facile assumptions and dazzling statistical manipulations. This essay, in moving toward a model for collection development within both specific collections and library systems as a whole, seeks to demonstrate the full range and complexity of relevant factors. An enlarged theoretical grasp should help highlight both the possibilities and the challenges of existing approaches. One result could be a shift toward gaming or simulation techniques as more realistic analytical tools. 相似文献
14.
Jason D. Phillips 《期刊图书馆员》2013,64(1):82-101
An annotated list is presented describing seventeen periodicals that cover significant aspects of the gay, lesbian, bisexual, and transgender (GLBT) community and their culture in whole or in part, with popular content rather than an academic or research focus. The titles included are a selective and representative sampling. The entry for each periodical includes the following information: periodical title, publisher/editor and address, basic information, publication data, content, Internet information, an abstract/annotation, and evaluative statement 相似文献
15.
SUMMARY Ariel files are the starting point for electronic delivery of interlibrary loan articles through ILLiad, Virginia Tech's interlibrary loan system. Despite some advantages to electronic delivery of articles to their desktops, a large majority of ILL customers continue to prefer print on paper delivery rather than electronic delivery. This fact has implications for introducing additional electronic services. Correctly choosing what services to impose on library customers, and what services to offer as value-added options, is fundamental to maintaining the credibility of libraries during these times of rapid change. 相似文献
16.
SUMMARY The state of Illinois funded a large scale Ariel project. This is a report of the project's successes and shortcomings. Although widely successful, additional training in the use of sophisticated hardware, primarily Minolta scanners, is needed. Data on sending and receiving is included. 相似文献
17.
《Slavic & East European Information Resources》2013,14(2-3):21-29
SUMMARY The authors discuss the development of the Slovak periodical press within its historical context and their expectations for its future. The article covers general characteristics of Slovak magazines and newspapers from World War II to 1989, and their later development since the Velvet Revolution up to the present. It also discusses the Slovak press outside of Slovakia from the late nineteenth century. 相似文献
18.
Library Journal's 2011 Ebook Penetration and Use in U.S. Libraries Survey testifies to e-books’ increasing popularity in academic libraries. This review tracked literature published from 2005 that focused on academic librarians’ best practices for acquiring, cataloging, maintaining, and promoting e-books at their institutions. Some of these practices include implementing trial accesses, considering institutional requirements, providing an e-book presence in the library catalog, monitoring usage statistics, and utilizing the library Web site for promotional efforts. 相似文献
19.
《Slavic & East European Information Resources》2013,14(2-3):31-47
SUMMARY There are between fifteen and twenty U.S. libraries that collect publications from Central Asia, defined here as Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan. Collection development responsibility for these countries tends to rest with the Slavic selector, the Middle East selector, or both, divided by language. Vendors who can supply this material mostly also supply publications from other countries of the former Soviet Union. The author briefly discusses the history of collecting from this region and the results of a survey conducted in 2004. She presents evidence indicating that the main reason U.S. libraries are not receiving more books from the region is most likely because they are not being published, not because vendors are doing an inadequate job. 相似文献