Perhaps you should try some spelling variations:
2.1 germany » 21 germany, 2017 germany, 9.13 germany
tnf history » etf history, motif history, stone history
ref history » reef history, bief history, etf history
2f history » etf history, 7 history, reef history
2f 20th » 2.2 20th
20 20th » 90 20th, 2019 20th, 2020 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: %22agriculture AND state %2.1 germany %((((((2f history) OR (tnf history))) OR (((ref history) OR (brief history))))) OR (imf history)) %((2f 20th) OR (20 20th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %2.1 germany %((((((2f history) or (tnf history))) or (((ref history) or (brief history))))) or (imf history)) %((2f 20th) OR (20 20th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %2.1 germany %((((((2f history) or (tnf history))) or (((ref history) or (brief history))))) or (imf history)) %((2f 20th) OR (20 20th)) century%22*.