Perhaps you should try some spelling variations:
spoken conversations » spoken conversation, open conversations, taken conversations
oboen conversations » open conversations, bot conversations, about conversations
20th century » 18th century
etf history » reef history, imf history, tnf history
ref history » reef history, brief history, bief history
2f germany » 2 germany, 20 germany, 21 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: %christian ((spoken conversations) OR (oboen conversations)) %2f germany %((etf history) OR (ref history)) %2f 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%christian ((spoken conversations) OR (oboen conversations)) %2f germany %((etf history) or (ref history)) %2f 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %christian ((spoken conversations) OR (oboen conversations)) %2f germany %((etf history) or (ref history)) %2f 20th century%22*.