Perhaps you should try some spelling variations:
"new vaccine research : july 2007" » "new medicine research : july 2007", "novel vaccine research : july 2007", "anti vaccine research : july 2007", "new vaccine research : july 2008", "new vaccine research : july 2013", "new vaccine research : july 2012"
"multiple options research : july 2007" » "multiple locations research : july 2007", "multiple positions research : july 2007", "multiple solutions research : july 2007", "multiple actions research : july 2007", "multiple optics research : july 2007", "multiple operations research : july 2007", "multiple options research : july 2008", "multiple options research : july 2013", "multiple options research : 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: (("new vaccine research : july 2007") or ("multiple options research : july 2007"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("new vaccine research : july 2007") OR ("multiple options research : july 2007")).
• Removing quotes may allow a broader search: (( new vaccine research : july 2007 ) or ( multiple options research : july 2007 )).
• Adding a wildcard symbol may retrieve word variants: (("new vaccine research : july 2007") or ("multiple options research : july 2007"))*.