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

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 ))*.