Perhaps you should try some spelling variations:
union conversations » win conversations, design conversations, driven conversations
design conclusions » design conclusion
ref history » reef history, bief history, imf history
21 germany » 2.1 germany, 11 germany, 2 germany
2f history » 2.1 history, imf history, etf history
20 18th » 2017 18th, 2021 18th, 2018 18th

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 (design conclusions)) %21 germany %((2f history) OR (((ref history) OR (brief history)))) %20 18th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22christian ((union conversations) or (design conclusions)) %21 germany %((2f history) or (((ref history) OR (brief history)))) %20 18th century%22".
• Adding a wildcard symbol may retrieve word variants: %22christian ((union conversations) or (design conclusions)) %21 germany %((2f history) or (((ref history) OR (brief history)))) %20 18th century%22*.