You probably wouldn't purposely keep your research from a readership that might benefit from it. Yet when many authors sign traditional publication agreements they sign over all their rights - including copyright - to the publisher or journal.
More about Copyright!
RoMEO summarizes and ranks publisher copyright policies according to four color-coded categories. You can search RoMEO by publisher name, journal title, or ISSN.
For information on research funders' mandates and guidelines, see RoMEO's companion database, SHERPA/JULIET.