Qiqqa is by far the strongest solution for research and managing pdf's. Zotero, named as a comparison is weak as it does not allow pdf;s to be loaded into its interface - you need to use a pdf reader, which defeats its whole purpose. With Qiqqa documents in a library can be searched together. It has excellent maps of your libraries. It is not prefect, having a few glitches, but still is the only one of its kind.
Based on our record, Sciwheel seems to be more popular. It has been mentiond 1 time since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Https://sciwheel.com/ this is the one I use now as it's free. It costs more for one that will help you insert references into your papers. It will store PDF of my articles on their server. Source: about 1 year ago
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
EndNote - Accelerate Your Research. Save time, stay organized, collaborate with colleagues and get published with EndNote 20.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .
RefWorks - RefWorks is an online research management, writing & collaboration tool that helps researchers easily gather, manage, store & share information.
Citavi - Citavi is a program for Microsoft Windows that manages literary references and organizes organizational knowledge.