Perhaps you should try some spelling variations:
"international ecological economic studies" » "international technological economic studies", "international psychological economic studies", "international economics economic studies", "international ecological economics studies", "international political economic studies", "international ecological economic status"
"international policy economic theory" » "international poverty economic theory", "international prices economic theory", "national policy economic theory"

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

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