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

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