Something like this:

m.lcsearch=alltrim(THISFORM.txtSearch.VALUE)

SELECT DISTINCT st_ref, st_serial, ;
  iif(!empty(SUBSTR(stock.st_ldesc,1,120)),padr(stock.st_ldesc,120),padr(goods.go_ldesc,120)) as longdesc FROM stock, goods WHERE;
    ATC(m.lcsearch, stock.st_ref,1)>0;
    OR ATC(m.lcsearch,stock.st_serial,1)>0;
     OR ATC(m.lcsearch,stock.st_desc,1)>0;
    OR ATC(m.lcsearch,goods.go_desc,1)>0;
    OR ATC(m.lcsearch, SUBSTR(stock.st_ldesc,1,120),1)>0;
    OR ATC(m.lcsearch, SUBSTR(goods.go_ldesc,1,120),1)>0;
ORDER BY st_ref, st_serial