Perhaps you should try some spelling variations:
"backward willing" » "backward telling", "backward building", "backward binding"
"backward filling" » "backward telling", "backward filtering", "backward building"
"backward walking" » "backward masking", "backward tracking", "backward facing"

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: (((("backward willing") OR ("backward filling"))) OR ("backward walking")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"backward willing\") OR (\"backward filling\"))) or (\"backward walking\"))".
• Removing quotes may allow a broader search: (((( backward willing ) OR ( backward filling ))) or ( backward walking )).
• Adding a wildcard symbol may retrieve word variants: (((("backward willing") OR ("backward filling"))) or ("backward walking"))*.