Perhaps you should try some spelling variations:
serious conversation » curious conversations, serious conideration, versus conversation
20th century » 18th century
tnf history » etf history, ref history, motif history
imf history » brief history
2f germany » 2 germany, 20 germany, 21 germany
2f 20th » 20 20th, 2.2 20th
conversations » conversion, conventions

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 ((courageous conversations) OR (serious conversation)) %2f germany %((tnf history) OR (imf history)) %2f 20th century%22.
• Adding a wildcard symbol may retrieve word variants: %22christian ((courageous conversations) or (serious conversation)) %2f germany %((tnf history) or (imf history)) %2f 20th century%22*.