The paper describes an algorithm for determining the thematic proximity of magazines. The results of its software implementation can be used to solve the following urgent tasks: clasification of the scientometric indicators values in the evaluation of scientific activity; assessment of the main trends in the development of the main scientific areas; determination of the relationships between data in information systems for constructing ontologies and defining safety rules within the framework of the ABAC model; creation of effective and convenient mechanisms for searching for scientific information. A feature of the presented algorithm is the use of the co-authorship graph for constructing the thematic proximity metric and the ability to process magazines in different languages, which is difficult to implement for other thematic analysis algorithms based on the analysis of full-text information. The software implementation of the presented algorithm is used in practice in the scientometric system "ISTINA".