Perhaps you should try some spelling variations:
20th century » 18th century
2.1 germany » 2017 germany, 9.13 germany, 9.14 germany
21 germany » 11 germany, 2 germany, 20 germany
8 germany » 1918 germany
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 %((((8 germany) OR (7 germany))) OR (((21 germany) OR (2.1 germany)))) %brief history %2020 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((((8 germany) OR (7 germany))) or (((21 germany) or (2.1 germany)))) %brief history %2020 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((((8 germany) OR (7 germany))) or (((21 germany) or (2.1 germany)))) %brief history %2020 20th century%22*.