Perhaps you should try some spelling variations:
when conversations » open conversations, agent conversations, chain conversations
win conversations » wine conversation, wins conversation, chain conversations
reef history » brief history, reeves history, reef fishery
20th century » 18th century
etf history » imf history, tnf history, beruf history
ref history » brief history, bief history, imf history
21 germany » 2.1 germany, 11 germany, 2 germany
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 ((win conversations) OR (when conversations)) %21 germany %((etf history) OR (((ref history) OR (reef history)))) %2f 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22christian ((win conversations) OR (when conversations)) %21 germany %((etf history) or (((ref history) or (reef history)))) %2f 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %22christian ((win conversations) OR (when conversations)) %21 germany %((etf history) or (((ref history) or (reef history)))) %2f 20th century%22*.