Perhaps you should try some spelling variations:
serious conversation » curious conversations, serious conideration, versus conversation
curious conversion » curious confession, curious conversations, cur's conversion
20th century » 18th century
ref history » reef history, brief history, bief history
imf history » brief history
12 germany » 11 germany, 12 german, 14 germany
2f 20th » 20 20th, 2.2 20th

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: %22christian ((curious conversion) OR (serious conversation)) %12 germany %((ref history) OR (imf history)) %2f 20th century%22.
• Adding a wildcard symbol may retrieve word variants: %22christian ((curious conversion) or (serious conversation)) %12 germany %((ref history) or (imf history)) %2f 20th century%22*.