Perhaps you should try some spelling variations:
christianity upon » christianity among, christianity along, christianity from
christian unity » christian union, christian laity, christian divinity
christian upon » christians upon, christian union, christ upon
20th century » 18th century
ref history » reef history, brief history, bief history
20 germany » 7 germany, 8 germany, 5 germany
2 germany » 12 germany, 7 germany, 2 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: %((((christian upon) OR (christianity upon))) OR (christian unity)) conversations %((20 germany) OR (2 germany)) %ref history %2f 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((((christian upon) OR (christianity upon))) or (christian unity)) conversations %((20 germany) or (2 germany)) %ref history %2f 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %((((christian upon) OR (christianity upon))) or (christian unity)) conversations %((20 germany) or (2 germany)) %ref history %2f 20th century%22*.