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

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