Academic Search Premier: an excellent database to rummage around in after you've sampled what articles are available in a HOLLIS "everything" search.
Academic Search Premier is, like HOLLIS, multidisciplinary in its coverage, also provides you with a range of article types (some scholarly, some not).
But while still broad, it's a smaller universe than HOLLIS: you'll search across books, articles, and book reviews. Depending on your topic, searching in ASP may seem more manageable.
Familiar and current, it also searches full-text, which makes it different from the other databases (including HOLLIS) on this guide.
Full-text searching can be an advantage when you've got a very narrow topic or are seeking a "nugget" that traditional database searching can't surface easily.
Google Scholar is perfectly acceptable for most general forays into scholarship; its algorithms are excellent and do return relevant results.
NOTE: One simple change can turn Google Scholar into what's effectively a Harvard database -- with links to the full-text of articles that the library can provide. Here's what to do: