Perhaps you should try some spelling variations:
"multi vaccine research : june 2011" » "multi action research : june 2011", "anti vaccine research : june 2011", "multi vaccine research : june 2013", "multi vaccine research : june 2014", "multi vaccine research : june 2012"
"multi operations research : june 2011" » "poultry operations research : june 2011", "port operations research : june 2011", "bus operations research : june 2011", "multi operations research : june 2013", "multi operations research : june 2014", "multi operations research : june 2012"

Try widening your search to All Fields.

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

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