Unfiltered information needs to be critically assessed by you. It is the weakest form of evidence and is summarized, but does not include grading of evidence. It presents the original work or experimental results of that article's author(s). This guide defines the different types and gives you databases and Websites you can use to search for this primary literature.
"I Don't Know What to Believe..." Making Sense of Science Stories by 
What is critical appraisal? by