送交者: JZ 于 2010-12-17, 13:16:13:

回答: Google Books, word frequency search, Shanghai, Bejing 由 JZ 于 2010-12-17, 13:05:32:

http://ngrams.googlelabs.com/graph?content=Beijing,+Shanghai&year_start=1800&year_end=2000&corpus=0&smoothing=3

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