There are several ways to broaden a topic.
1. Use the boolean operator OR to chain synomyms together.
e.g. internet or world wide web
2. Use the truncation symbol at the root of a word to retrieve all word forms.
Check the database help screen to determine the correct truncation symbol, which can vary.
Usual symbols are #,*,? .
e.g. librar# retrieves articles that have library, libraries, librarian, librarianship, etc.