Perhaps you should try some spelling variations:
"international ports economics series" » "international airports economics series", "international poverty economics series", "international efforts economics series", "international port economics series", "international sports economic series", "international arts economic series"
"regional political autonomy series" » "regional politics autonomy series", "national political autonomy series", "regional policy autonomy series", "regional political economy series", "regional political authority series", "regional political astronomy series", "regional political autonomy states"

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