Perhaps you should try some spelling variations:
"the frontier section" » "the frontiers section", "the frontier functions", "the frontal sections"
"the frontier second" » "the frontiers section"
"the frontier region" » "the frontal region"

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: (("the frontier section") OR ((("the frontier second") OR ("the frontier region")))).
• Removing quotes may allow a broader search: (( the frontier section ) or ((( the frontier second ) or ( the frontier region )))).
• Adding a wildcard symbol may retrieve word variants: (("the frontier section") or ((("the frontier second") or ("the frontier region"))))*.