Perhaps you should try some spelling variations:
location research » locations research, education research, action research
vaccine research » medicine research
multi location » multi option, multiple locations, multiplication _
multi vaccine » anti vaccine, multiple vaccines
july 2009 » july 2008, july 2007, july 2019

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( multi location research : july 2009 ) or ( multi vaccine research : july 2009 ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( multi location research : july 2009 ) OR ( multi vaccine research : july 2009 )).
• Adding a wildcard symbol may retrieve word variants: (( multi location research : july 2009 ) or ( multi vaccine research : july 2009 ))*.