Perhaps you should try some spelling variations:
option research » opinion research, action research, operations research
factor research » sector research, action research, water research
multi option » mali options, multiple options
multi factor » multi sector, _ multifactor, multi faceted
july 2009 » july 2006, july 2013, july 2012

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

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