Perhaps you should try some spelling variations:
"international political economic theories" » "international policy economic theories", "international political economy theories", "international ecological economics theories", "international political economic theory"
"national policy economic services" » "national policy ecological services", "national policy economic surveys", "national policy economic studies", "national poverty economic services"

You may be able to get more results by adjusting your search query.

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