Perhaps you should try some spelling variations:
20 germany » 2 germany, 8 germany, 5 germany
11 germany » 11 german, 1918 germany, 8 germany
2021 20th » 2021 24th, 2021 10th, 2023 20th
2020 20th » 2020 16th, 2020 2021, 2020 5th

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 %((20 germany) OR (((11 germany) OR (7 germany)))) %brief history %((2021 20th) OR (2020 20th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((20 germany) or (((11 germany) OR (7 germany)))) %brief history %((2021 20th) or (2020 20th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((20 germany) or (((11 germany) OR (7 germany)))) %brief history %((2021 20th) or (2020 20th)) century%22*.