Perhaps you should try some spelling variations:
interactions series » interactions between
immigration regimes » migration regimes, migration regime, integration regimes
cost interactions » host interactions, host interaction, iot interactions
a immigration » _ immigration, 2 immigration, 5 immigration
supply cost » supply costs
support a » support _

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply cost interactions series. ) or ( support a immigration regimes. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply cost interactions series. ) OR ( support a immigration regimes. )).
• Adding a wildcard symbol may retrieve word variants: (( supply cost interactions series. ) or ( support a immigration regimes. ))*.