Perhaps you should try some spelling variations:
"world economic and financial system." » "world economic and financial sector.", "world economy and financial system."
"world economic and financial services." » "world economy and financial services.", "world economic and financial series."
"world economic and financial studies." » "world economy and financial studies."

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 services.") or ("world economic and financial system."))) or ("world economic and financial studies."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("world economic and financial services.") OR ("world economic and financial system."))) OR ("world economic and financial studies.")).
• Removing quotes may allow a broader search: (((( world economic and financial services. ) or ( world economic and financial system. ))) or ( world economic and financial studies. )).
• Adding a wildcard symbol may retrieve word variants: (((("world economic and financial services.") or ("world economic and financial system."))) or ("world economic and financial studies."))*.