Great for most topics in psychology including clinical, positive, abnormal, aging, and organizational psyc topics. Includes over three million citations of journal articles, book chapters, books, dissertations, and technical reports.
Great for evolutionary, biological, or cognitive psychology topics. Contains over 22 million citations to biomedical literature including empirical research, literature reviews, and other articles.
Diagnostic and Statistical Manual of Mental Disorders DSM-5 by 
