For personal interest there is the Home license. Unfortunately that does not allow access to some of the toolboxes, and is limited to 1000 virtual blocks (Simulink).
However the Home license cannot be used for research papers, as those are considered to not be "personal" use. Unfortunately the only applicable license for research papers is the full license..
If you retired from a research organization or university, then as far as Mathworks is concerned, it is acceptable for the organization to grant you Emeritus status of some form or other, and continue to provide you with access through their licence, if they are so inclined.