Perhaps you should try some spelling variations:
"international policy economic studies" » "international poverty economic studies", "international prices economic studies", "national policy economic studies", "international policy economic status"
"international rent economic services" » "international arena economic services", "international event economic services", "international real economic services", "international rent economics series", "international rent ecological services", "international rent economic surveys", "international recent economic services", "international great economic services", "international next economic services"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("international policy economic studies") or ("international rent economic services"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("international policy economic studies") OR ("international rent economic services"))*.
• Removing quotes may allow a broader search: (( international policy economic studies ) or ( international rent economic services ))*.