Perhaps you should try some spelling variations:
"world bank chief economists" » "world bank chief economist", "world bank how economists", "world bank can economists", "world beck chief economists", "world bank chinese economists"
"world best women economists" » "world best modern economists", "world best women economic", "world best women chemists", "world test women economists", "world better women economists", "world beat women economists", "world best workmen economists", "world obese women economists"
"world's best women economists" » "world's best modern economists", "world's best women economic", "world's best women chemists", "world's most women economists", "world's first women economists", "world's beat women economists", "world's best workmen economists", "world's obese women economists"

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 bank chief economists") OR ((("world best women economists") OR ("world's best women economists")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"world bank chief economists\") or (((\"world best women economists\") OR (\"world's best women economists\"))))".
• Removing quotes may allow a broader search: (( world bank chief economists ) or ((( world best women economists ) OR ( world's best women economists )))).
• Adding a wildcard symbol may retrieve word variants: (("world bank chief economists") or ((("world best women economists") OR ("world's best women economists"))))*.