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