Perhaps you should try some spelling variations:
multiple vaccines » multiple access, multiple crises, multiple faces
vaccines research » vaccine research, practices research, accidents research
july 2006 » july 2008, july 2009, july 2012
june 2009 » june 2007, june 2008, june 2019
july 2007 » july 2008, july 2012, july 2020

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

• Performing a fuzzy search may retrieve terms with similar spellings: multiple vaccines research : ((((july 2006) OR (june 2009))) OR (((july 2007) OR (july 2013))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "multiple vaccines research : ((((july 2006) OR (june 2009))) OR (((july 2007) OR (july 2013))))".
• Adding a wildcard symbol may retrieve word variants: multiple vaccines research : ((((july 2006) OR (june 2009))) OR (((july 2007) OR (july 2013))))*.