Although still in Beta Google Scholar can be a great research tool.
About Google Scholar: "Google Scholar enables you to search specifically for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research."
For example, use Google to search "Mercury". Note your results range from articles on spacecraft and automobiles to newspapers with Mercury in the title. Now do the same search at Google Scholar. You will get all sorts of scholarly articles on the chemical. Add 'god' and get articles on the Roman god and mythology.