Perhaps you should try some spelling variations:
union conversations » win conversations, design conversations, driven conversations
design conclusions » design conclusion
2017 germany » 20 germany, 17 germany, 2006 germany
20th century » 18th century
ref history » reef history, brief history, bief history
21 germany » 11 germany, 2 germany, 20 germany
90 20th » 20 20th, 94 20th, 1990 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 ((union conversations) OR (design conclusions)) %((21 germany) OR (2017 germany)) %ref history %90 20th century%22.
• Adding a wildcard symbol may retrieve word variants: %22christian ((union conversations) or (design conclusions)) %((21 germany) or (2017 germany)) %ref history %90 20th century%22*.