Perhaps you should try some spelling variations:
"international ecological economic surveys" » "international technological economic surveys", "international psychological economic surveys", "international economics economic surveys", "international ecological economics surveys", "international ecology economic surveys", "international ecological economic studies", "international ecological economic systems"
"international political economic theory" » "international policy economic theory", "international political economy theory", "international ecological economics 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 surveys") or ("international political economic theory"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("international ecological economic surveys") OR ("international political economic theory")).
• Removing quotes may allow a broader search: (( international ecological economic surveys ) or ( international political economic theory )).
• Adding a wildcard symbol may retrieve word variants: (("international ecological economic surveys") or ("international political economic theory"))*.