There are many (many!) places to find articles, including the Articles tab on the Duke Libraries homepage, Google Scholar, and plain old Google. I'm highlighting a few sources below that will be particularly effective for this course.
Broad coverage of scholarly journal articles in the sciences and beyond. Strict keyword searching (so use your search strategies), citation network info (cited/citing publications), author affiliation searching, among other options. Can refine results by date, article type (research, review, etc.), and more.