I'm looking for a pdf reader like, but with folders sorting and a research engine. Maybe with even more interesting features, what are your suggestions?
To read papers, I use a standard PDF viewer (or image viewer, for some old papers which I've scanned in).<p>To organize papers, I use Zotero. <a href="https://en.wikipedia.org/wiki/Comparison_of_reference_management_software" rel="nofollow">https://en.wikipedia.org/wiki/Comparison_of_reference_manage...</a> has a long list of reference management software, some of which have modified PDF readers which allow, for example, user annotations.