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 prices economic theory" » "international crises economic theory", "international prices econometric theory", "international services economic theory"

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