Rather that typing a long sentence, enter something like 'document separator'. This will return all the articles with the words 'document' or the word 'separator' in the title or keyword list.
To perform regular expression queries on non latin characters you need to reference their character types. In the case of the Chinese, Japanese, Korean characters sets, use the \p{IsCJKUnifiedIdeographs} selector. For example, to capture only CJK characters from a mixed language text bloc
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