The research is devoted to the use of symbolic expressions for informational queries. The problem of information search, is discussed with use of designations and special symbols in various subject domains. It is proposed to use specialized thesauri, where along with natural language definitions are present symbolic expressions. This approach allowed refining a retrieval, regardless of the language of the original source and can also be applied to the identification of critical situations on the basis of an analysis of symbolic indicators underlying the structured data. Proposed technology comparison texts by analogy and mechanism for replenishment of the thesaurus, as well as the possibility of establishing additional semantic relationships that may speed up the search for information in a critical situation. It is offered to use these data for finding of 'special points' in subject domains and to operate them.