Perhaps you should try some spelling variations:
"international policy economic theories" » "international poverty economic theories", "national policy economic theories", "international policy economic theory", "international policy economics series"
"international prices economic services" » "international prices economics series", "international prices ecological services", "international prices economic studies", "international crises economic services", "international prices econometric services", "international services economic services"

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