1. PubMed: PubMed is a free database that provides access to a wide range of biomedical literature, including research articles, reviews, and clinical studies. It is maintained by the National Center for Biotechnology Information (NCBI) and is a valuable resource for researchers in the field of medicine and related disciplines. 2. IEEE Xplore: IEEE Xplore is a digital library that provides access to research articles, conference papers, and technical standards in the fields of engineering, computer science, and technology. It is maintained by the Institute of Electrical and Electronics Engineers (IEEE) and is widely used by researchers, engineers, and students in these disciplines. 3. PsycINFO: PsycINFO is a database that focuses on psychology and related disciplines, providing access to research articles, books, and other publications in the field of psychology. It is maintained by the American Psychological Association (APA) and is a valuable resource for researchers, students, and practitioners in the field of psychology. 4. EconLit: EconLit is a database that focuses on the field of economics, providing access to research articles, working papers, and other publications in the field of economics. It is maintained by the American Economic Association (AEA) and is a valuable resource for researchers, economists, and students in the field of economics. 5. Scopus: Scopus is a multidisciplinary database that provides access to research articles, conference papers, and other publications in a wide range of disciplines. It is maintained by the Elsevier publishing company and is a valuable resource for researchers in various fields, including science, social sciences, and humanities.