1. A method implemented on a computing device by a processor for searching heterogeneous interrelated entities comprising: receiving a heterogeneous interrelated entities search query; searching, in a unified space, for results to the heterogeneous interrelated entities search query, the results including a set of heterogeneous interrelated entities having a plurality of entity types, the unified space based on one or more relationships between multiple heterogeneous entities; constructing a multiple-type graph for one or more heterogeneous entity types; extracting co-occurrence matrices from the multiple-type graph based on interactions between pairs of the one or more heterogeneous entity types; forming one or more entity vectors for each of the one or more heterogeneous entity types based on the co-occurrence matrices; concatenating the one or more entity vectors to form a unified matrix that represents the multiple heterogeneous entities in the unified space; and presenting the results as a plurality of lists, each list of the plurality of lists comprising search result entities of a same entity type.
2. The method of claim 1 , wherein the heterogeneous interrelated entities search query comprises at least two heterogeneous entities having different entity types.