Perhaps you should try some spelling variations:
frontiers collection » containers collection, frontiers section, reuters collection
frontiers selection » frontiers section, frontier section, frontier electron
folders collection » folders connections, holders collective, leaders collection

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: %22the ((((frontiers collection) OR (folders collection))) OR (frontiers selection))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22the ((((frontiers collection) OR (folders collection))) or (frontiers selection))%22".
• Adding a wildcard symbol may retrieve word variants: %22the ((((frontiers collection) OR (folders collection))) or (frontiers selection))%22*.