Perhaps you should try some spelling variations:
"world board working paper" » "world word working paper", "world hard working paper", "world world working paper", "world toward working paper", "works board working paper", "world born working paper"
"world band working papers" » "world bandes working papers", "world based working papers", "world hard working papers", "world brand working papers", "world bank working papers", "world bandar working papers"
"world hand working papers" » "world hard working papers", "world chang working papers", "world und working papers", "world hands working papers", "world hans working papers", "world had working papers"
"world bond working paper" » "world bonds working paper", "world bold working paper", "world bone working paper", "world beyond working paper", "world blind working paper", "world blood working paper"

Try widening your search to All Fields.

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("world band working papers") OR ("world hand working papers"))) OR ((("world bond working paper") OR ("world board working paper")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"world band working papers\") OR (\"world hand working papers\"))) or (((\"world bond working paper\") or (\"world board working paper\"))))".
• Removing quotes may allow a broader search: (((( world band working papers ) OR ( world hand working papers ))) or ((( world bond working paper ) or ( world board working paper )))).
• Adding a wildcard symbol may retrieve word variants: (((("world band working papers") OR ("world hand working papers"))) or ((("world bond working paper") or ("world board working paper"))))*.