Perhaps you should try some spelling variations:
"international ecological economic studies" » "international economics economic studies", "international economic economic studies", "international economies economic studies", "international ecological economics studies", "international ecological economic status", "international ecological economic surveys"
"international political economic theories" » "international policy economic theories", "international political economy theories", "international ecological economics theories", "international political economic theory"

Try widening your search to All Fields.

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