Thematic Search in the Electronic Catalogs of National Libraries

The article deals with means of thematic search by the library classification in electronic catalogs of national libraries. Comparative features of various information and library search engines are considered. It is found out that the presentation of the classification system is important in the form of an interactive hierarchical thematic knowledge tree, which allows the user to restrict the search to a certain thematic branch. A necessary element of modern inter-library communication is also the required introduction to the national library system of thematic search of an international classification system, such as UDC.