Perhaps you should try some spelling variations:
ref history » reef history, brief history, bief history
21 germany » 2 germany, 20 germany, 7 germany
11 germany » 11 german, 1918 germany, 7 germany
2023 26th » 2023 6th, 2023 5th, 2023 7th
90 20th » 20 20th, 94 20th, 1990 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) OR (11 germany)) %ref history %((2023 26th) OR (90 20th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((21 germany) OR (11 germany)) %ref history %((2023 26th) or (90 20th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((21 germany) OR (11 germany)) %ref history %((2023 26th) or (90 20th)) century%22*.