Perhaps you should try some spelling variations:
20th century » 18th century
tnf history » etf history, motif history, stone history
ref history » reef history, bief history, etf history
21 germany » 2.1 germany, 11 germany, 2 germany
20 20th » 90 20th, 2019 20th, 2020 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: %22agriculture AND state %21 germany %((((tnf history) OR (((ref history) OR (brief history))))) OR (imf history)) %20 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %21 germany %((((tnf history) or (((ref history) OR (brief history))))) or (imf history)) %20 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %21 germany %((((tnf history) or (((ref history) OR (brief history))))) or (imf history)) %20 20th century%22*.