Perhaps you should try some spelling variations:
accident research » action research, vaccine research
options research » operations research, action research, opinion research
scale options » call options, share options, care options
june 2011 » june 2013, june 2014, june 2012
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 accident research : june 2011 ) or ( scale options research : july 2009 ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( multi accident research : june 2011 ) OR ( scale options research : july 2009 )).
• Adding a wildcard symbol may retrieve word variants: (( multi accident research : june 2011 ) or ( scale options research : july 2009 ))*.