Perhaps you should try some spelling variations:
"multiple vaccines research : july 2011" » "multiple access research : july 2011", "multiple crises research : july 2011", "multiple faces research : july 2011", "multiple vaccine research : july 2011", "multiple practices research : july 2011", "multiple accidents research : july 2011", "multiple vaccines research : july 2013", "multiple vaccines research : july 2012", "multiple vaccines research : july 2015"
"multi recent research : july 2011" » "multi current research : july 2011", "mali recent research : july 2011", "multi agent research : july 2011", "multi client research : july 2011", "multi recent research : july 2013", "multi recent research : july 2012", "multi recent research : july 2015"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("multi recent research : july 2011") or ("multiple vaccines research : july 2011"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("multi recent research : july 2011") OR ("multiple vaccines research : july 2011")).
• Removing quotes may allow a broader search: (( multi recent research : july 2011 ) or ( multiple vaccines research : july 2011 )).
• Adding a wildcard symbol may retrieve word variants: (("multi recent research : july 2011") or ("multiple vaccines research : july 2011"))*.