Perhaps you should try some spelling variations:
"supply mass migration policies." » "supply mass immigration policies.", "supply mass migration policy.", "supply mass education policies.", "supply case migration policies.", "supply main migration policies.", "supply many migration policies."
"supply crowd integration theory." » "supply crowd integration through.", "supply crowd information theory.", "supply crowd innovation theory.", "supply grid integration theory.", "supply rfid integration theory.", "supply beyond integration theory.", "supply growth integration theory.", "supply cost integration theory.", "supply from integration theory."

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: (("supply mass migration policies.") OR ("supply crowd integration theory."))~.
• Removing quotes may allow a broader search: (( supply mass migration policies. ) or ( supply crowd integration theory. ))~.
• Adding a wildcard symbol may retrieve word variants: (("supply mass migration policies.") or ("supply crowd integration theory."))*.