Perhaps you should try some spelling variations:
upon conversations » union conversations, open conversations, spoken conversations
christian upon » christians upon, christian union, christianity upon
reef history » brief history, reeves history, reef fishery
2.1 germany » 21 germany, 2017 germany, 9.13 germany
2021 20th » 2021 24th, 2020 20th, 2021 10th
2.2 20th » 2020 20th, 2023 20th, 2022 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 conversations %2.1 germany %reef history %((2.2 20th) OR (2021 20th)) century%22.
• Adding a wildcard symbol may retrieve word variants: %christian upon conversations %2.1 germany %reef history %((2.2 20th) or (2021 20th)) century%22*.