EndNote Web Mobile: Look up citations via your mobile device.
Mendeley: Free citation management program that works on your desktop & the web, with social networking & group collaboration features. Sign up for a free account here.
Doximity: The physician's private network, accessible wherever you are.
Webicin@: A curated set of online medical resources in social media for patients & medical professionals.
BrowZine: Combines & arranges individual articles from databases in an intuitive newsstand, then delivers them to you in an easy-to-use format on iPad or Android tablets.
Docphin: Stay up to date on the latest medical research in your favorite journals for iOS & Android.
Evernote: Save your ideas, search by keyword, tag or even printed & handwritten text inside images.
PDF Annotation Apps: Includes links & summaries of free & paid apps. From iMedical Apps.