The archive for the now defunct Grace Magazine (which I edited c December 1995-March 2001) is now available online in digital form (January 1981-December 2014) on the sbhs website. The search facility does not seem to be available for finding issues but once into an edition it can be searched throughly. The website is here.
Meanwhile, over at the Reformation Today website all the editions from 1970-1987 are available in digital format (issues 1-100). There appears to be no search facility. The websire is here.