Perhaps you should try some spelling variations:
"international ecological economics services" » "international technological economics services", "international psychological economics services", "international economics economics services", "international ecological economic services", "international ecological economics series", "international ecological economics soviet"
"international political economic theories" » "international policy economic theories", "international political economy theories", "international political economic theory", "international political economics series"

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