The LC (Library of Congress) subject heading search uses a specific, controlled vocabulary for describing Library material. Try these subject headings search for browsing, or more focused search resuslts.
From the Library's homepage (http://www.lib.rowan.edu/campbell), hover over the Find link and then choose Catalog. Once on this page choose the Advanced search option. Now key in your topic (say, economics); then move further down the page to the Format option. Click on the drop down arrow to find the type of resource you want (i.e. DVD). The best match for this medium is listed as "videorecording." Choosing to search this topic as a subject results in 25 titles that meet your requirements; these 25 are a mixture of DVDs and vioderecordings, so you will simply have to peruse the list to find the DVD notation.