Presently, it does not.
But if it were to offer such a feature, how might you expect it to work?
As Rick said, there's nothing out of the box.
If you're not afraid to get your hands dirty, you can add some filtering yourself: http://www.wvanweelden.eu/blog/2014/02/16/adobe-robohelp-filtering-webhelp-search-results
Also check out the comments, where you'll find an alternative way for adding the filter.