谁来回答一下啊，求高手

试试这个是否可行：
findit heckman tobit

SJ-11-2 st0224  . . . .  Fitting fully observed recursive mixed-process models
        (help cmp, ghk2 if installed) . . . . . . . . . . . . . . . D. Roodman
        Q2/11   SJ 11(2):159--206
        fits simultaneous-equation fully observed recursive
        mixed-process models