Perhaps you should try some spelling variations:
ref history » reef history, brief history, bief history
21 germany » 11 germany, 2 germany, 20 germany
2023 26th » 2023 6th, 2023 5th, 2023 7th
90 20th » 94 20th, 1990 20th
20 20th » 2019 20th, 2020 20th, 2023 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 %ref history %((2023 26th) OR (((90 20th) OR (20 20th)))) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %21 germany %ref history %((2023 26th) or (((90 20th) OR (20 20th)))) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %21 germany %ref history %((2023 26th) or (((90 20th) OR (20 20th)))) century%22*.