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 price economic theories" » "international prices economic theories", "international policy economic theories", "international center economic theories", "international price economic theory", "international price economics series", "international rice economic theories", "international peace economic theories"

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