Perhaps you should try some spelling variations:
serious conversation » curious conversations, serious conideration, versus conversation
design conversations » design considerations, design construction, design conclusions
union conversations » win conversations, driven conversations, invent conversations
20th century » 18th century
ref history » reef history, brief history, bief history
2.1 germany » 21 germany, 2017 germany, 9.13 germany
imf history » brief history
2f history » etf history, tnf history, 7 history
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 ((((union conversations) OR (((courageous conversations) OR (serious conversation))))) OR (design conversations)) %((7 germany) OR (2.1 germany)) %((((2f history) OR (ref history))) OR (imf history)) %2f 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22christian ((((union conversations) or (((courageous conversations) or (serious conversation))))) or (design conversations)) %((7 germany) or (2.1 germany)) %((((2f history) OR (ref history))) or (imf history)) %2f 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %22christian ((((union conversations) or (((courageous conversations) or (serious conversation))))) or (design conversations)) %((7 germany) or (2.1 germany)) %((((2f history) OR (ref history))) or (imf history)) %2f 20th century%22*.