A Harvard law professor who conducted a study of black partners at large firms 17 years ago said there hasn’t been much of an improvement in the intervening years.In 1999, David B. Wilkins wrote in “Partners Without Power? A Preliminary Look at Black Partners in Corporate Law Firms,” that the number of black partners in large corporate firms was “embarrassingly small,” that law firms had trouble retaining the few black associates they hire and that few of those black lawyers made equity …