Perhaps you should try some spelling variations:
2.1 germany » 2017 germany, 9.13 germany, 9.14 germany
ref history » reef history, brief history, bief history
imf history » brief history
21 germany » 11 germany, 2 germany, 20 germany
2021 18th » 2021 13th, 2021 16th, 2021 6th
20 18th » 2017 18th, 2018 18th, 2019 18th

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 %((21 germany) OR (2.1 germany)) %((ref history) OR (imf history)) %((20 18th) OR (2021 18th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((21 germany) or (2.1 germany)) %((ref history) or (imf history)) %((20 18th) OR (2021 18th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((21 germany) or (2.1 germany)) %((ref history) or (imf history)) %((20 18th) OR (2021 18th)) century%22*.