Perhaps you should try some spelling variations:
"world based working paper" » "world base working paper", "world based parking paper", "world basic working paper", "word based working paper", "world case working paper", "gold based working paper"
"world brand working paper" » "world band working paper", "world branch working paper", "world board working paper", "word brand working paper", "world bank working paper"
"world brand working papers" » "world band working papers", "world branch working papers", "world board working papers", "word brand working papers", "world bank working papers"

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 based working paper") OR ((("world brand working paper") OR ("world brand working papers")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"world based working paper\") or (((\"world brand working paper\") OR (\"world brand working papers\"))))".
• Removing quotes may allow a broader search: (( world based working paper ) or ((( world brand working paper ) OR ( world brand working papers )))).
• Adding a wildcard symbol may retrieve word variants: (("world based working paper") or ((("world brand working paper") OR ("world brand working papers"))))*.