APA recommends the use of homepage URLs for online journals and publisher websites (and not complete URLs). Complete URLs however, should be used for harder to find materials.
Online Version of a Print Journal
Brookhart, S. M. (2008). Feedback that fits [Electronic version]. Educational Leadership. 65(4), 54-59. Retrieved from http://www.ascd.org/
Online Journal Only (not from a database)
Yerrick, R., & Johnson, J. (2009). Meeting the needs of middle grade science learners through pedagogical and technological intervention. Contemporary Issues in Technology and Teacher Education. 9(3). Retrieved from http://www.citejournal.org/
(American Psychological Association, 2010, p. 185)