My thanks to Klaus Graf. For a German-language blog post complaining about the lack of interest in making a good OA search engine, he has obtained and shown a screenshot of two results from OAFindr (by 1science aka One Science) for mongolian folk song. These keywords were used for my December 2015 group-test of OA search engines.
Neither of the two OAFindr results is in JURN, because they both come from a title published by the Canadian Center of Science and Education, a publisher which has long been on Beall’s List.
Update, Nov 2017: OAFindr is now called 1Findr.