The literature database ACCESSSS of the canadian McMaster University Health Information Research Unit (HiRU) claims "to help provide current best evidence for clinical decisions".
It is freely available on the clinic and faculty network or after free registration. It mainly addresses physicians, because it allows the simultaneous search in DynaMed Plus and for rated or commented systematic reviews and studies.
The main part is the McMaster PLUS database with ratings of thousands of selected articles earch year.
The search results are clearly structured in a Hierarchy of Evidence, supported by a colour system.