Perhaps you should try some spelling variations:
upon conversations » union conversations, spoken conversations, human conversations
open conversations » roman conversations, content conversations, based conversations
bief history » brief history, brief hystory, imf history
20th century » 18th century
ref history » reef history, brief history, imf history
21 germany » 2.1 germany, 11 germany, 2 germany
2020 20th » 2020 16th, 2020 5th, 2020 2021
agent » agents

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: %christian ((upon conversations) OR (((open conversations) OR (agent conversations)))) %21 germany %((ref history) OR (bief history)) %2020 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%christian ((upon conversations) or (((open conversations) OR (agent conversations)))) %21 germany %((ref history) or (bief history)) %2020 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %christian ((upon conversations) or (((open conversations) OR (agent conversations)))) %21 germany %((ref history) or (bief history)) %2020 20th century%22*.