Search results
Results from the WOW.Com Content Network
Subject indexing is used in information retrieval especially to create bibliographic indexes to retrieve documents on a particular subject. Examples of academic indexing services are Zentralblatt MATH, Chemical Abstracts and PubMed. The index terms were mostly assigned by experts but author keywords are also common.
Uniterm is a subject indexing system introduced by Mortimer Taube in 1951. The name is a contraction of "unit" and "term", referring to its use of single words as the basis of the index, the "uniterms". Taube referred to the overall concept as "Coordinate Indexing", but today the entire concept is generally referred to as Uniterm as well.
Index terms can consist of a word, phrase, or alphanumerical term. They are created by analyzing the document either manually with subject indexing or automatically with automatic indexing or more sophisticated methods of keyword extraction. Index terms can either come from a controlled vocabulary or be freely assigned.
Library classification systems are one of the two tools used to facilitate subject access. The other consists of alphabetical indexing languages such as Thesauri and Subject Headings systems. The practice of library classification is a form of the more general task of classification. The work consists of two steps.
The word indexing service is today mostly used for computer programs, but may also cover services providing back-of-the-book indexes, journal indexes, and related kinds of indexes. [ 2 ] An indexing and abstracting service is a service that provides shortening or summarizing of documents and assigning of descriptors for referencing documents.
A bibliographic index is a bibliography intended to help find a publication. Citations are usually listed by author and subject in separate sections, or in a single alphabetical sequence under a system of authorized headings collectively known as controlled vocabulary , developed over time by the indexing service. [ 1 ]
In a number of countries it is the main classification system for information exchange and is used in all types of libraries: public, school, academic and special libraries. [17] [18] [19] UDC is also used in national bibliographies of around 30 countries. Examples of large databases indexed by UDC include: [20]
Comparison with subject-specific indexes has further revealed the geographical and topic bias – for example Ciarli [25] found that by comparing the coverage of rice research in CAB Abstracts (an agriculture and global health database) with WoS and Scopus, the latter "may strongly under-represent the scientific production by developing ...