8. The word retrieval method according to claim 6 , further comprising: setting a character string defining a document type; and comparing each word obtained from the morphological analysis result with the character string and extracting the word when the word corresponds to the character string.
8. The word retrieval method according to claim 6 , further comprising: setting a character string defining a document type; and comparing each word obtained from the morphological analysis result with the character string and extracting the word when the word corresponds to the character string. 9. The word retrieval method according to claim 8 , wherein the character string includes information of notation and a part of speech of the character string, the comparing being comparing of the notation or the notation and part of speech of each word in the text, with the notation or the notation and part of speech of the character string, the extracting being extracting of a word corresponding to the notation or the notation and part of speech of the character string.