Perhaps you should try some spelling variations:
"research written paper" » "research write paper", "research within paper", "research writing paper", "research written after"
"research white paper" » "research while paper", "research write paper", "research what paper"
"research white papers" » "research while papers", "research write papers", "research what papers", "research state papers"
"research which papers" » "research ethics papers", "research what papers", "research why papers", "research which players", "research which popery", "research which popes"

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: (((((("research written paper") OR ("research white paper"))) OR ("research white papers"))) OR ("research which papers")).
• Removing quotes may allow a broader search: (((((( research written paper ) or ( research white paper ))) or ( research white papers ))) or ( research which papers )).
• Adding a wildcard symbol may retrieve word variants: (((((("research written paper") or ("research white paper"))) or ("research white papers"))) or ("research which papers"))*.