Perhaps you should try some spelling variations:
"Policy research workshop part" » "Policy research workshop para", "Policy research workshop paris", "Policy research workshop papers"
"policy research working paper" » "policy research 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: (("policy research working paper") OR ("Policy research workshop part")).
• Removing quotes may allow a broader search: (( policy research working paper ) or ( Policy research workshop part )).
• Adding a wildcard symbol may retrieve word variants: (("policy research working paper") or ("Policy research workshop part"))*.