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 » 11 germany, 2 germany, 20 germany
2021 20th » 2021 24th, 2020 20th, 2021 10th

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 %ref history %2021 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 %ref history %2021 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %((((christian upon) OR (christians upon))) or (christian union)) conversations %21 germany %ref history %2021 20th century%22*.