This site offers a large (millions) updated data base of resources as a free repository for PDF books and articles for your research. Simply visit and search to your heart’s content for magazines, scientific articles, comics, fiction, standards, etc. at: http://gen.lib.rus.ec/
An example: NEU staff entered, “stem cells” in the search-area after ticking the category, scientific articles. These hotlinked resources popped up instantly: http://gen.lib.rus.ec/scimag/?q=stem+cells and there aren’t cheesy advertisements like many “free” websites. Happy Research!
(Gratitude to Dr Nancy Ash for the featured photo from her private collection.)