Perhaps you should try some spelling variations:
21 germany » 11 germany, 2 germany, 20 germany
8 germany » 7 germany, 1918 germany
2021 18th » 2021 13th, 2021 16th, 2021 6th
2017 18th » 2017 14th, 2017 16th, 2017 4th
20 18th » 2018 18th, 2019 18th, 2015 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 %((8 germany) OR (21 germany)) %brief history %((((20 18th) OR (2021 18th))) OR (2017 18th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((8 germany) or (21 germany)) %brief history %((((20 18th) OR (2021 18th))) or (2017 18th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((8 germany) or (21 germany)) %brief history %((((20 18th) OR (2021 18th))) or (2017 18th)) century%22*.