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

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