Non-indexed databases and search engines (e.g. Google) generally gather their citations and related materials from multiple sources. A Basic search examines available fields to find the entered terms. Some, like Web of Science, are totally dependent on how the author (or journal) has described the article. Databases that pull from a indexed databases (e.g. USC Libraries search and ProQuest) may also offer access to the indexed terms (e.g. MeSH) applied by those databases. See Non-Indexed Examples for tips on searching specific databases.
For information on the non-indexed USC Libraries search, visit:
Some databases allow full text searching. For academic journal databases, this means the word(s) you enter could be only in a footnote or a reference. Not all fields in all databases can be searched. Use Advanced Search options (when available) to search additional fields.
Databases that search the full text include:
Sometimes it's difficult to tell the difference between a database and a search engine. ProQuest, for example, includes over 130 individual databases - and options to search across two or more of the underlying databases. Generally searching across multiple databases (equivalent to a search engine) requires both keyword and phrase searching. A subject search depends on the subjects applied within the underlying databases. In ProQuest, if you cannot locate a Thesaurus or subject heading hierarchy, then the database is probably not indexed.
Search engines that allow searching across multiple databases include the following. See Non-indexed Examples for details on searching tips for these databases.