Citavi is a research software that helps users organize, structure, and share their research. It provides an all-in-one solution for researching, organizing, and citing sources. With Citavi, users can store and manage their references, quotes, and notes in one place. It also enables users to quickly find and access the most relevant information from the thousands of sources available online. Citavi also provides a suite of tools to help users structure and organize their research, such as creating concept maps and hierarchical outlines, and automatically generating bibliographies. The Citavi app also enables users to collaborate with colleagues, and share their research with others. Finally, Citavi offers an in-app citation generator, allowing users to quickly create citations for their work.
Discontinued development and support of Docear was stopped in August 2017. The latest version, 1.2, released in December 2015, can still be downloaded from the official website. http://www.docear.org/2017/02/05/docears-online-services-are-down-recommendation-user-registration-backup/
It is totally free It has a good user interface and works quite well.
Discontinued As the developer stated in February 2017, the software is no longer being developed: https://sourceforge.net/p/textcite/discussion/616111/thread/91d6f4bc/#e988 The latest version, 1.4, released in September 2009, can still be Still downloaded from the official website
Company discontinued / unreachable website
Discontinued software is discontinued, but still available for download from http://www.debenu.com/products/desktop/debenu-pdf-benubird/.
Zotero
Mendeley
Qiqqa
Docear
JabRef
EndNote
Papers
BibSonomy
ReadCube
Paperpile
wizdom.ai
Weava
Bookends
TextCite
EasyBib
PDF Stacks
Biblioscape
RefWorks
KBibTeX
Benubird PDF
Citavi 5 has much more functionality than Mendeley. Mendeley cannot search through annotations, cannot distinguish between different types of notes (direct quotes, indirect quotes, comments, main ideas, etc.) and more features.