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