Using the LibrarySearch tool on the library home page, you can opt for doing and E-book search up front or you can limit your results once displayed to books "available online".
Use the keyword marketing in conjunction with one or two other words of interest, e.g., a particular demographic, women marketing. An alternate approach is to use the keyword consumers instead of marketing: women consumers. Larger companies will have entire books devoted to them, e.g., Starbucks or Microsoft, but they might also appear in the table of contents as a case study. Try searches that combine the name of a company and marketing: Starbucks marketing. Also consider doing a search for the name of the industry or product: coffee marketing.