Perhaps you should try some spelling variations:
christians upon » christians among, christians from, christians being
christian upon » christianity upon, christ upon, christian u
20th century » 18th century
ref history » reef history, brief history, bief history
21 germany » 2 germany, 20 germany, 7 germany
11 germany » 11 german, 1918 germany, 7 germany
2.2 20th » 2020 20th, 2023 20th, 2021 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 (christians upon))) OR (christian union)) conversations %((21 germany) OR (11 germany)) %ref history %2.2 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((((christian upon) or (christians upon))) or (christian union)) conversations %((21 germany) OR (11 germany)) %ref history %2.2 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %((((christian upon) or (christians upon))) or (christian union)) conversations %((21 germany) OR (11 germany)) %ref history %2.2 20th century%22*.