Background information is a crucial step in the medical research process. This is especially important if you are new to a topic, as preliminary research will not only explain the basics of a topic, but will allow you to learn information like disease prevalence and potential treatment options, which will influence your research topic. If you are searching for clinical research, this will also help identify potential keywords for your search, so you shouldn't miss this step!
Evidence in these resources may vary from expert opinion to high levels of evidence. These resources can also be Point of Care resources in that they can be used to answer questions while caring for the patient, but they may or may not be evidence-based.