Search for journal articles on most topics. This multi-disciplinary database is a good place to start if you don't know where else to begin. (EBSCO)
Search for peer-reviewed articles in geography, geology and ecology. (Elsevier)
Search across Biological Abstracts, Medline, Preprint Citation Index, PQ Dissertations and Theses, Web of Science Core (Science Citation Index, Social Sciences Citation Index, and Arts & Humanities Citation Index), and Zoological Record. Track, evaluate, and compare journals and articles. Tools included are the number of citations, the journal's impact factor, and other metrics. (Clarivate)
Search an index of journal articles in the liberal arts and the sciences. This link cross-searches the Core databases, including Science Citation Index, Social Sciences Citation Index, and Arts & Humanities Citation Index. It's part of the Web of Science platform and can also be used to track, evaluate, and compare journals and articles. Tools included are the number of citations, the journal's impact factor, and other metrics. (Clarivate)