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