Google Books Ngram Viewer

Graph these comma-separated phrases:
case-insensitive
between and from the corpus with smoothing of .  
Search in Google Books:

1900 - 1940 1941 - 1951 1952 - 1954 1955 - 1992 1993 - 2000 石油 Chinese
1900 - 1928 1929 - 1968 1969 - 1972 1973 - 1993 1994 - 2000 战争 Chinese
1900 - 1973 1974 - 1991 1992 - 1993 1994 - 1996 1997 - 2000 能源 Chinese
1900 - 1921 1922 - 1986 1987 - 1990 1991 - 1995 1996 - 2000 Chinese
1900 - 1971 1972 - 1997 1998 1999 2000 环保 Chinese

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