Google Books Ngram Viewer

Graph these comma-separated phrases:
case-insensitive
between and from the corpus with smoothing of .  
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1800 - 1932 1933 - 1993 1994 - 1996 1997 - 2004 2005 - 2008 doctrine of emptiness English
1800 - 1956 1957 1958 - 1985 1986 - 2002 2003 - 2008 theory of emptiness English

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