These discovery tools are the primary means of finding journal articles relevant to your research topic. Some of these tools are “databases” that have full-text journals associated with them. PubMed (or MEDLINE) is an extensive index but does not directly have full-text articles associated with it. PubMed Central (to which you get access via PubMed) provides journal articles that are “open access” -- and available in full-text. MEDLINE has some linked full-text articles available.