Perhaps you should try some spelling variations:
"multiple generations research : july 2013" » "multi generation research : july 2013", "multimap generation research : july 2013", "multiple migrations research : july 2013", "multiple generation research : july 2013", "multiple generational research : july 2013", "multiple generating research : july 2013"
"multi ratios research : july 2019" » "multi rating research : july 2019", "multi relations research : july 2019", "multi actions research : july 2019", "multi radio research : july 2019", "multi rate research : july 2019", "multi option research : july 2019", "multi ratios research : july 2012", "multi ratios research : july 2015", "multi ratios research : july 2020"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("multiple generations research : july 2013") OR ("multi ratios research : july 2019"))~.
• Removing quotes may allow a broader search: (( multiple generations research : july 2013 ) or ( multi ratios research : july 2019 ))~.
• Adding a wildcard symbol may retrieve word variants: (("multiple generations research : july 2013") or ("multi ratios research : july 2019"))*.