Subject searches are more focused than keyword searches and can provide more accurate results.
Library catalogues and most article databases support subject searches.
Most library catalogues and article databases will let you search by subject.
The advantage of subject searching is a more focused search.
However, when you start, you likely will not know what pre-determined subject terms describe a topic.
Here are some examples of database subject terms generated from a search for "marketing to children":
And here is an example from the Library Catalogue:
A good strategy for subject searching is:
A subject search can be especially useful for finding out about authors, rather than finding works by the author. E.g., books or articles about Oscar Wilde rather than works by Oscar Wilde.
Choose a Subject search vs. a Keyword search in the Library Catalogue or an article database to see the difference.