Perhaps you should try some spelling variations:
"quality classroom research : july 2007" » "quality class research : july 2007", "quality classroom research : july 2013", "quality classroom research : july 2012", "quality classroom research : july 2020"
"multi accident research : july 2008" » "multi current research : july 2008", "multi recent research : july 2008", "multi vaccine research : july 2008", "multi client research : july 2008", "multi accident research : july 2013", "multi accident research : july 2012", "multi accident research : july 2020"

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: (("quality classroom research : july 2007") or ("multi accident research : july 2008"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("quality classroom research : july 2007") OR ("multi accident research : july 2008")).
• Removing quotes may allow a broader search: (( quality classroom research : july 2007 ) or ( multi accident research : july 2008 )).
• Adding a wildcard symbol may retrieve word variants: (("quality classroom research : july 2007") or ("multi accident research : july 2008"))*.