Perhaps you should try some spelling variations:
"imf working papers; working paper" » "adf working papers; working paper", "brief working papers; working paper"
"off working papers; working paper" » "offer working papers; working paper", "adf working papers; working paper", "office working papers; working paper"
"hf working papers; working paper" » "adf working papers; 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: (("hf working papers; working paper") OR ((("imf working papers; working paper") OR ("off working papers; working paper")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"hf working papers; working paper\") or (((\"imf working papers; working paper\") OR (\"off working papers; working paper\"))))".
• Removing quotes may allow a broader search: (( hf working papers; working paper ) or ((( imf working papers; working paper ) OR ( off working papers; working paper )))).
• Adding a wildcard symbol may retrieve word variants: (("hf working papers; working paper") or ((("imf working papers; working paper") OR ("off working papers; working paper"))))*.