Perhaps you should try some spelling variations:
upon conversations » union conversations, open conversations, spoken conversations
bief history » brief history, brief hystory, imf history
ref history » reef history, brief history, imf history
21 germany » 11 germany, 2 germany, 20 germany
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 (agent conversations)) %21 germany %((ref history) OR (bief history)) %2.2 ((20th century) OR (18th century))%22.
• Adding a wildcard symbol may retrieve word variants: %christian ((upon conversations) or (agent conversations)) %21 germany %((ref history) or (bief history)) %2.2 ((20th century) or (18th century))%22*.