Perhaps you should try some spelling variations:
"world economic and financial systems." » "world economic and financial system.", "world economic and financial statements."
"world economic and financial series." » "world economic and financial service.", "world economic and financial studies.", "world economic and financial stress."
"world economy and financial series." » "world economy and financial service.", "world economy and financial studies.", "world economy and financial stress."

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: (("world economic and financial systems.") or ((((("world economic and financial series.") OR ("world economic and financial services."))) or ("world economy and financial series."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("world economic and financial systems.") OR ((((("world economic and financial series.") OR ("world economic and financial services."))) OR ("world economy and financial series.")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"world economic and financial systems.\") or (((((\"world economic and financial series.\") OR (\"world economic and financial services.\"))) or (\"world economy and financial series.\"))))".
• Removing quotes may allow a broader search: (( world economic and financial systems. ) or ((((( world economic and financial series. ) OR ( world economic and financial services. ))) or ( world economy and financial series. )))).
• Adding a wildcard symbol may retrieve word variants: (("world economic and financial systems.") or ((((("world economic and financial series.") OR ("world economic and financial services."))) or ("world economy and financial series."))))*.