There are many sources of evidence and lots of these are collected into some of the large medical research databases.
NHS staff are able to register for an NHS OpenAthens account, which gives access to hundreds of health research articles via journals and healthcare databases such as MEDLINE, EMBASE, CINAHL and the British Nursing Index. To register for an OpenAthens account visit NHS Evidence.
Many health research articles are available for free in open access journals, which do not usually require a login. You can search for journals through The National Institute for Health and Care Excellence.
National Institute for Health Research (NIHR) funds much of the research which takes place in the UK, and publishes accounts of its research which can be accessed for free from the NIHR Journals Library.
In order to make sound evidence-based decisions, we understand that you will usually want to assess the body of evidence around a particular issue, rather than basing a decision on one paper or a small number of papers. In these cases we recommend that you access a systematic review which, as the name suggests, is a systematic consideration of all research papers published on a particular topic. A systematic review will exclude studies with poor methods, too-small sample sizes or other methodological failings, and will focus on the well-conducted studies. It will provide a summary of the findings and where possible will synthesize the findings of comparable trials into a meta-analysis – which effectively ‘adds together’ comparable studies’ findings to give an overall result. Systematic reviews can be found in various journals and databases, but an ideal place to check first is the Cochrane Database of Systematic Reviews which is an open access source of reviews which come from the Cochrane Collaboration, an international network of collaborators and recognised as the gold standard for high quality, trusted information. Also you can access Cochrane Podcasts.
You can then assess the systematic review using the CASP checklist to see if it is valid, reviewing the results to determine whether they will apply locally. Download the checklist through the Critical Appraisal Skills Programme (CASP) website.