Perhaps you should try some spelling variations:
ref history » reef history, brief history, bief history
21 germany » 11 germany, 20 germany, 7 germany
2 germany » 7 germany, 2 german, 8 germany
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 (2 germany)) %ref history %((90 20th) OR (_ 20th)) century%22.
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((21 germany) or (2 germany)) %ref history %((90 20th) or (_ 20th)) century%22*.