Perhaps you should try some spelling variations:
design conversations » design construction, design conclusions, design consideration
reef history » brief history, reeves history, reef fishery
20th century » 18th century
ref history » brief history, bief history, imf history
17 germany » 7 germany, 11 germany, 12 germany
2f 20th » 20 20th, 2.2 20th

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: %22christian ((design conversations) OR (design considerations)) %17 germany %((ref history) OR (reef history)) %2f 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22christian ((design conversations) or (design considerations)) %17 germany %((ref history) OR (reef history)) %2f 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %22christian ((design conversations) or (design considerations)) %17 germany %((ref history) OR (reef history)) %2f 20th century%22*.