Perhaps you should try some spelling variations:
"world economic and financial systems." » "world economic and financial system.", "world economic and financial statements."
"world economy and financial stress." » "world economy and financial distress.", "world economy and financial access.", "world economy and financial strength."
"world economy and financial services." » "world economy and financial series."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((((("world economy and financial burden.") or ("world economy and financial stress."))) or ("world economy and financial services."))) or ("world economic and financial systems."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((((("world economy and financial burden.") OR ("world economy and financial stress."))) OR ("world economy and financial services."))) OR ("world economic and financial systems.")).
• Removing quotes may allow a broader search: (((((( world economy and financial burden. ) or ( world economy and financial stress. ))) or ( world economy and financial services. ))) or ( world economic and financial systems. )).
• Adding a wildcard symbol may retrieve word variants: (((((("world economy and financial burden.") or ("world economy and financial stress."))) or ("world economy and financial services."))) or ("world economic and financial systems."))*.