Subject ontologies are the basis of every information system that describes scientific knowledge. A particular simplified case of a subject ontology is the indexes of classification systems, such as international UDC, ICI, Russian State Rubricator for Scientific and Technical Information (SRSTI) and Library Bibliografic Classification (LBC). A more developed example of a subject ontology is thematic thesauri containing terms related to a certain field of science or technology, with their

more »

... hical and horizontal connections. When considering the architecture of the Common Digital Space of Scientific Knowledge (CDSSK), a subject ontology is understood as a generalized structure that includes both thesaurus elements and associated indexes of various classification systems that describe this scientific area. This article presents the results of research related to the construction of subject ontologies based on the previously developed system for supporting terminological dictionaries and proposes a methodology for identifying new key terms for its replenishment. The methodology is based on the use of existing citation databases (CDB), such as WEB of Science and Scopus for English-language publications and the Russian Citation Index for Russian-language publications. The methodology presupposes the division of the scientific area into a number of sections, the selection from the CDB of the core of articles related to each section, and from the articles - the author's key terms, which, in conjunction with the corresponding sections of the classification systems, should form the basis of the subject ontology of this scientific area.