Perhaps you should try some spelling variations:
opinion research » action research
factor research » sector research, action research, water research
multi opinion » multi option
multi factor » multi sector, _ multifactor, multi faceted
june 2013 » july 2013
july 2012 » july 2013

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( multi factor research : june 2013 ) or ( multi opinion research : july 2012 ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( multi factor research : june 2013 ) OR ( multi opinion research : july 2012 )).
• Adding a wildcard symbol may retrieve word variants: (( multi factor research : june 2013 ) or ( multi opinion research : july 2012 ))*.