The Articles+ search on the Franklin catalog page can be helpful for broad searches, known-item searches, and easy access to newspaper sources. For more in-depth searching in a subject, it's best to consult the individual specialized databases:
To generate a list of databases by your subject of interest, navigate to the Penn Libraries homepage, click on the "Quick E-Lookup" tab, and select a subject from the drop-down menu. Below is the list generated for Historic Preservation: