Perhaps you should try some spelling variations:
frontiers collection » containers collection, folders collection, reuters collection
frontier reflections » further reflections, proper reflections, other reflections
folders connections » orders connections, models connections, codes connections
frontiers selection » frontier section, frontier electron, frontiers regulation
frontiers section » frontier section

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