xqbib is an Fx-based Qddb application. Hence, all the built-in features and behavior of other Fx-based applications are present in xqbib. For example, you can search on any field and configure the many options available via the ``Configure'' pulldown menu.
Reference the Qddb User's Guide http://www.hsdi.com/qddb/usersguide
for details on how to operate the xqbib window in general.