Perhaps you should try some spelling variations:
"multiple operations research : july 2013" » "multiple generations research : july 2013", "multiple migrations research : july 2013", "multiple options research : july 2013"
"mali educational research : july 2009" » "maxi educational research : july 2009", "early educational research : july 2009", "art educational research : july 2009", "mali educational research : july 2008", "mali educational research : july 2007", "mali educational research : 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: (("mali educational research : july 2009") or ("multiple operations research : july 2013"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("mali educational research : july 2009") OR ("multiple operations research : july 2013")).
• Removing quotes may allow a broader search: (( mali educational research : july 2009 ) or ( multiple operations research : july 2013 )).
• Adding a wildcard symbol may retrieve word variants: (("mali educational research : july 2009") or ("multiple operations research : july 2013"))*.