1. A computer-implemented method, comprising: at a computer having memory, a display, and one or more processors, receiving a search keyword provided by a user, wherein the search keyword satisfies a predefined expression pattern; determining an archetype for the search keyword; identifying a query operator for the archetype, wherein the query operator includes a generalized expression of the search keyword; applying the identified query operator to a document; identifying a chunk within the document that satisfies the identified query operator, wherein the chunk does not include an instance of the search keyword; and returning the chunk for display to the user.