The greatest benefit to using library databases is their flexibility. After you run your search, you'll have many options for refining your result set. These options almost always appear on the left side of the screen. You can limit your results to articles from a certain range of years, articles in specified languages, and particular document types.
What are document types? Those are the different kinds of materials that get published: journal articles, conference papers, books, and even specific types of articles like reviews.
A review article is great when you're doing a research project. It's when a professional researcher has done a thorough literature review on a topic, summarized and synthesized the existing work, and published it along with a nice big bibliography. If you find a good, recent review article on your topic, you'll have the bulk of your searching done for you.
Libraries call these specialized search engines databases. They provide more options to refine your search than free resources like Google Scholar, allowing you to get closer to exactly what you want. Library databases are great for finding articles from scholarly and trade journals, conference papers, and other publications.
Scopus is probably going to be the best place to start; it includes all the material from IEEE as well as most content from most major publishers, so it's an efficient place to start. Scopus does not contain most ACM material, so it may be a good idea to search ACM Digital Library separately.