You can learn about "controlled vocabulary" and what it means to use it in a search over in the "Starting your research" tab of this guide. Controlled vocabulary is probably most useful when searching databases. While google is good at recognizing natural language, databases are designed to pull sources based on indexed metadata. Below is an example of an index search of the term "fan" in APA PsycInfo. You'll notice that "fan" or "sports fan", is not technically a controlled term. Instead, the index suggests using the term "Sports Spectators". Using this term will help find sources no matter the terminology used by the authors to describe their work, and accounts for spelling and word variations, as well as synonyms
In most databases, you can choose to search different fields, meaning that you can choose to search for your chosen terms in just the title, or abstract, or author fields. This can be helpful in many ways, but one example is that sometimes a keyword, such as "fan", may show up in less relevant fields, like an author's name. If you limit your search to just the title, keywords, or abstract, you will avoid also pulling articles with authors named Fan. If you are searching PsycInfo, just click on the "Select a Field (optional)" drop down menu available in "Advanced Search", and select which field you would like to search for the given term.
