Perhaps you should try some spelling variations:
christian upon » christians upon, christianity upon, christ upon
bief history » brief history, brief hystory, imf history
15th century » 18th century, 19th century, 17th century
ref history » reef history, brief history, imf history
21 germany » 2.1 germany, 11 germany, 2 germany
2020 15th » 2020 16th, 2020 5th, 2020 4th

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 (christian union)) conversations %21 germany %((ref history) OR (bief history)) %2020 15th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((christian upon) OR (christian union)) conversations %21 germany %((ref history) or (bief history)) %2020 15th century%22".
• Adding a wildcard symbol may retrieve word variants: %((christian upon) OR (christian union)) conversations %21 germany %((ref history) or (bief history)) %2020 15th century%22*.