Searches that look for all variations of a word can be helpful, but sometimes you need to search for a word or phrase exactly as spelled.
How you do this differs from database to database. In CanLII, use EXACT( ) around the word you are searching for, e.g. EXACT(AIDS). CanLII usually searches for variants of the word, but using EXACT will force it to search for exactly what you have specified.
Quicklaw and WestlawNext Canada both default to searching for both the singular and plural of a search term, rather than all the variants; this means you won’t get as many false hits as on CanLII. However, if you do want to search for an exact term, use singular ( ) or plural ( ) in Quicklaw (e.g. plural (AID) for AIDS) and use #term in WestlawNext (e.g. #AIDS). In Lexis Advance just use quotation marks (e.g. “AIDS”).