Perhaps you should try some spelling variations:
22christian union » christian union, christian upon
christian unity » christian union, christian laity, christian divinity
reef history » brief history, reeves history, reef fishery
20 germany » 2 germany, 7 germany, 8 germany
21 germany » 2.1 germany, 11 germany, 2 germany

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: %((22christian union) OR (christian unity)) conversations %((20 germany) OR (21 germany)) %reef history %2f ((20th century) OR (18th century))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((22christian union) or (christian unity)) conversations %((20 germany) or (21 germany)) %reef history %2f ((20th century) OR (18th century))%22".
• Adding a wildcard symbol may retrieve word variants: %((22christian union) or (christian unity)) conversations %((20 germany) or (21 germany)) %reef history %2f ((20th century) OR (18th century))%22*.