Perhaps you should try some spelling variations:
"international political economy series" » "international policy economy series", "international political economic series"
"international economics ecological studies" » "international economics technological studies", "international economics economic studies", "international economics economics studies", "international economics ecological services", "international economics clinical studies"

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