The presence of structure inside XML documents poses the hard challenge of providing fiexible query matching methods for effective retrieval of results. In this paper we present an approach that faces this issue in a twofold fashion: 1) it exploits new approximations on data structure; 2) it provides a relevance ranking method that takes into account the degree of correctness and completeness of results with respect to a given query, as well as the degree of cohesion of data retrieved.