15. A graphical user interface (GUI), comprising: a display device configured to display: a first user-interface element configured to receive a source document; a second user-interface element configured to display search results of related documents based on semantic entities extracted from the source document; and a third user-interface element configured to receive user-adjusted search criteria from a user, wherein the user-adjusted search criteria include a user-adjusted entity-extraction sensitivity, and wherein the entity-extraction sensitivity indicates a number of semantic entities that are to be extracted from the source document; wherein search results of related documents are updated 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.
20. The GUI of claim 15 , wherein the display device is further configured to display a fifth user-interface element which allows a user to adjust the entity-extraction sensitivity corresponding to a number of entities that are to be extracted from the source document.