Perhaps you should try some spelling variations:
21 germany » 2.1 germany, 11 germany, 2 germany
2f history » imf history, etf history, ref history
20 20th » 2019 20th, 2020 20th, 2023 20th
90 20th » 94 20th, 1990 20th
94 24th » 94 4th, 24 24th, 94 20th
94 14th » 14 14th, 94 11th, 94 19th

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 %2f history %((20 20th) OR (((90 20th) OR (((94 24th) OR (94 14th)))))) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %21 germany %2f history %((20 20th) or (((90 20th) or (((94 24th) OR (94 14th)))))) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %21 germany %2f history %((20 20th) or (((90 20th) or (((94 24th) OR (94 14th)))))) century%22*.