Perhaps you should try some spelling variations:
"multiple options research : july 2006" » "multiple locations research : july 2006", "multiple positions research : july 2006", "multiple solutions research : july 2006", "multiple actions research : july 2006", "multiple optics research : july 2006", "multiple operations research : july 2006", "multiple options research : july 2008", "multiple options research : july 2007", "multiple options research : july 2009"
"multi factor research : july 2012" » "multi factors research : july 2012", "multi sector research : july 2012", "multi actors research : july 2012", "multi actor research : july 2012", "_ multifactor research : july 2012", "multi factor research : 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: (("multiple options research : july 2006") or ("multi factor research : july 2012"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("multiple options research : july 2006") OR ("multi factor research : july 2012")).
• Removing quotes may allow a broader search: (( multiple options research : july 2006 ) or ( multi factor research : july 2012 )).
• Adding a wildcard symbol may retrieve word variants: (("multiple options research : july 2006") or ("multi factor research : july 2012"))*.