We had studied fcr indexing, before the information retrieval, regarding such as theme "To what extent can the extraction of terms cover the contents of original materials such as specifications of chemical patents ?" so that in this report, it is discussed, on a point of view "Subjectextending in technical literature regarding chemical patent specifications." Namely, that is studied on what forms extend, change or exhibit in text, important parts of text, important terms extracted from text, by subiect analysis, which base upon indexing, classification, keywords and abstracts. And difficulties of covering terms are based on terminal parts of subject-extending. Because, in these parts in text, subidct turn into detail, in a concreate form and increase to many terms. But, such difficulities should be solved considerably, if the terms extracted are coded in classification. In addition, extension of subject, repeating oneself on subjdco-extending and unfairness (in means of classification) on subject-extending are considered.

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