Perhaps you should try some spelling variations:
1918 germany » 8 germany
imf history » brief history
ref history » reef history, brief history, bief history
2f history » 2.1 history, etf history, tnf history
11 germany » 11 german, 7 germany, 8 germany
21 germany » 2.1 germany, 2 germany, 20 germany
2020 5th » 2020 16th
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: %22agriculture AND state %((21 germany) OR (((11 germany) OR (1918 germany)))) %((((2f history) OR (ref history))) OR (imf history)) %((2f 20th) OR (2020 5th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((21 germany) or (((11 germany) OR (1918 germany)))) %((((2f history) or (ref history))) or (imf history)) %((2f 20th) or (2020 5th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((21 germany) or (((11 germany) OR (1918 germany)))) %((((2f history) or (ref history))) or (imf history)) %((2f 20th) or (2020 5th)) century%22*.