The Directory of Open Access Journals defines Open Access as:
"journals that use a funding model that does not charge readers or their institutions for access. From the BOAI definition[1] of 'open access' we take the right of users to 'read, download, copy, distribute, print, search, or link to the full texts of these articles...or use them for any other lawful purpose' as mandatory for a journal to be included in the Directory." (DOAJ Webiste).
All of the journals listed in the DOAJ are peer reviewed, and there are quality controls in place to weed out what are known as "predatory publishers."
The search function in DOAJ looks like this: 
Some of the journals listed in the DOAJ that may be of use to you:
It may be easier to search for articles within the journals, rather than through the DOAJ website.
"PubMed Central® (PMC) is a free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM)." (PMC website)
PMC's search box is located at the top of the webpage.
They also offer an advanced search that looks similar to the databases you may be used to from the library's resources.
