On March 11, Scopus released TopCited, a free service which 
lists the most-cited recent articles in various 
disciplines.... Users can view the top 20 articles from the 
past 3, 4, or 5 years in one of 26 subject areas, and view 
the authors' institutions on a Google Map... All of the 
current top 20 papers (across all subjects, from the past 5 
years) have OA versions online.