Perhaps you should try some spelling variations:
reef history » brief history, reeves history, reef fishery
20th century » 18th century
2.1 germany » 21 germany, 2017 germany, 9.13 germany
12 germany » 11 germany, 12 german, 14 germany
2 germany » 7 germany, 2 german, 8 germany
11 german » 1 german
2f 20th » 20 20th, 2.2 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 %((((((2 germany) OR (12 germany))) OR (2.1 germany))) OR (11 german)) %reef history %2f 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((((((2 germany) OR (12 germany))) or (2.1 germany))) or (11 german)) %reef history %2f 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((((((2 germany) OR (12 germany))) or (2.1 germany))) or (11 german)) %reef history %2f 20th century%22*.