1. A computer-executable method for searching related documents, the method comprising: receiving a source document; searching for related documents based on semantic entities extracted from the source document; receiving user-adjusted search criteria from a user, wherein the user-adjusted search criteria include a user-adjusted entity-extraction sensitivity, and wherein the user-adjusted entity-extraction sensitivity indicates a number of semantic entities that are to be extracted from the source document; and updating search results of related documents based on the user-adjusted search criteria, wherein the user-adjusted search criteria include the number of semantic entities that are extracted from the source document.