Perhaps you should try some spelling variations:
"international political economy theories" » "international policy economy theories", "international political economics theories", "international political economy series", "international political economy theory"
"national poverty economic theories" » "national poverty economic theory", "national poverty economics series", "national property economic theories", "national forestry economic theories", "national policy 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: (("national poverty economic theories") or ("international political economy theories"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("national poverty economic theories") OR ("international political economy theories")).
• Removing quotes may allow a broader search: (( national poverty economic theories ) or ( international political economy theories )).
• Adding a wildcard symbol may retrieve word variants: (("national poverty economic theories") or ("international political economy theories"))*.