Controlled vocabulary--also known as subject headings, subject terms, thesaurus terms, or descriptors--are the official indexing terms used by the organizers of a database to describe each concept so that all items on the same topic have the same descriptor or subject heading.
In contrast to “free Web” searching, controlled vocabularies organize the information in a database. You can click on a heading to see all the other items that have the same heading. You can also combine the terms in a new search to find items on that topic.
Your search results will be more focused and more relevant, since you will be searching directly in the subject or descriptor field.
Controlled Vocabulary searching starts by exploring the Thesaurus or Subject headings of a database (see individual database tutorials for more information). Search through the thesaurus or subject headings and combine relevant terms that apply to your topic.
The pearl growth technique relies on finding or having one very good resource with which to begin. Once you've found a great article or book, you can begin analyzing how that article is defined.
Basically, you are trying to recreate a search that would have found your starting article, which will pull in similar articles.
A citation search is a search for other articles that have made reference to a particular book or article. A citation search will show you who has mentioned a particular article, where, and how many times.
Citation searching is also very useful if you are trying to trace the evolution of a scholarly idea or theory. When you find other works that have cited a particular work, you can see how the idea has been changed or added to over time.
Citation searching can also be useful if you have one relevant article but are having trouble finding others. Use the citations in your one relevant article to find the resources your article used. This is considered moving up the ancestry of a citation line, and it can often lead to new discoveries on your topic.
Some databases allow you to see citation information (e.g. JSTOR). Others will have citation links, allowing you to navigate by clicking on a citation that interests you and find more information (Google Scholar).
To use Google Scholar for citation searching, either enter an article title, author, or search by keyword.
Each result has a "cited by[N]" link below it. This tells you how many times an article was cited.
Clicking on this link will bring you to another results page that lists all the citing articles.