First, go to "Advanced Search" - and think about limits you could set to your search.
You can also browse - follow the "ebooks" on the top menu (see below)
GVRL - "Gale Virtual Reference Library" - contains encyclopedias and specialized sources for example "Business Plans Handbook" or "Encyclpedia of Managment". Select "Business" from the list of subjects (left side) to browse the titles.
PLS (Peninsula Library Collection) ebooks are searchable through the PLS book catalog. NOTE: The PLS' multiple ebook databases require setting separate passwords etc. - see http://www.plsinfo.org/ebooks
Safari has business, technical and web design books. Try the link below for some examples.