※使用圖表方式呈現各年代的詞頻變化。可搜尋多組單字，每組單字用「,」分開，例如「民主,科學」可比較「民主」與「科學」各年代出現次數的差異。 Noted: Use diagram to display Word Frequency Over Time. Please use comma ',' to separate word groups. For instance, '民主,科學'. By doing so, the discrepancy of occurrence frequency by year can be observed.