There are a number of operations to select from in advanced search.
FUNCTION : OR
The search such as below for example will populate results for candidates that have a broad match for 'Sales' as we have not entered that in inverted commas.
Candidates that have an exact match for the term 'CRM' in their resumes.
Since we have selected 'files' these searches will be through all resumes in your data base.
FUNCTION : AND
Two separate search operations will search through both criteria mentioned.
This search operation will show candidates in your database that have a broad search for 'Sales' and an exact match for 'CRM'.
Hence, this pool of candidates should reduce from the previous search.