You can easily search a majority of the Penn Libraries journal titles about General/Internal Medicine in Browzine.
Internal Medicine — Medical Specialties A-N — University of Pennsylvania — BrowZine
Below are direct links to a selection of these titles.
Approaches to Chronic Kidney Disease: a guide for primary care providers and non-nephrologists by 
Approach to Internal Medicine: A Resource Book for Clinical Practice by 
Huppert's Notes: Pathophysiology and Clinical Pearls for Internal Medicine by 
