Perhaps you should try some spelling variations:
2.1 germany » 21 germany, 2017 germany, 9.13 germany
ref history » reef history, brief history, bief history
imf history » brief history
2f history » etf history, tnf history, reef history
2020 18th » 2020 16th, 2020 15th, 2020 8th

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 (ref history))) OR (imf history)) %2020 18th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %2.1 germany %((((2f history) OR (ref history))) or (imf history)) %2020 18th century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %2.1 germany %((((2f history) OR (ref history))) or (imf history)) %2020 18th century%22*.