There's now a search extension for the Bibliographie der deutschen Sprach- und Literaturwissenschaft available at
http://www.bdsl-online.de/bdsl/hilfe/bdsl_hilfe_html.html?schnell_suchen.htm
(that's the Hilfe link at the top of the BDSL page).

There's also a BDSL link that can be installed on the Google tool bar.