Perhaps you should try some spelling variations:
upon conversations » union conversations, open conversations, spoken conversations
christian upon » christians upon, christian union, christianity upon
20th century » 18th century
2.1 germany » 21 germany, 2017 germany, 9.13 germany
ref history » reef history, brief history, bief history
2023 20th » 2023 26th, 2023 10th, 2020 20th