Method and apparatus for providing search service based on knowladge service

The purpose of the present invention is to provide a method and apparatus for providing a search service based on a knowledge structure, which are capable of extracting important keywords from a document, representing the relationship between the extracted keywords as a knowledge structure, searching for desired information with reference to the knowledge structure and providing a user with the desired information. The present invention relates to a method and apparatus for providing a search service based on a knowledge structure. The method for providing a search service comprises the steps of: searching for a document corresponding to a query input by a user and providing the document; generating a knowledge structure corresponding to the document and additionally providing the knowledge structure; additionally searching for related documents including a selected keyword when one among a plurality of keywords included in the knowledge structure is selected; comparing and analyzing the knowledge structure of the related documents and the knowledge structure of the generated document to calculate the similarity between the documents; and performing a document recommendation operation or a document providing operation based on a result of the similarity calculation.