Perhaps you should try some spelling variations:
"supply trade integration schemes." » "supply trade integration schengen.", "supply trade irrigation schemes.", "supply trade integration regimes.", "supply case integration schemes."
"supply south interaction series." » "supply south interactions series.", "supply south interaction studies.", "supply south interaction terms.", "supply youth interaction series.", "supply south integration series.", "supply youth integration series.", "supply southern interaction series.", "supply costs interaction series.", "supply cost interaction series."

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 trade integration schemes.") OR ("supply south interaction series."))~.
• Removing quotes may allow a broader search: (( supply trade integration schemes. ) or ( supply south interaction series. ))~.
• Adding a wildcard symbol may retrieve word variants: (("supply trade integration schemes.") or ("supply south interaction series."))*.