When she was a bottle blond in the General Hospital-obsessed early '80s, Janine Turner was known to millions as the daytime soap's less-than-brilliant bombshell Laura Templeton the Laura after Genie Francis of ''Luke and Laura'' fame. But underneath the long locks and vacant looks was a smart, nervous teen with little patience for the bland roles assigned to beautiful women. ''I was always the Victim of the Week, yelling, 'Oh, help me!' just before Knight Rider or the A-Team would come to rescue me,'' says the 28-year-old, who has finally found acclaim playing the brisk, businesslike, and anything-but-dumb Alaskan pilot Maggie O'Connell in CBS' comedy hit Northern Exposure. Turner grew up in Euless, Tex.; a veteran of child beauty pageants, she headed for New York at a tender 15, where the Wilhelmina model agency helped train most of the twang out of her accent. By 20, she was engaged to Alec Baldwin (the marriage never happened) and winning semi-steady work on TV. But by the time Exposure came along, the still-single actress recalls, ''I was crushed, out of money, alone in the city like in a Dostoyevski novel.'' So her defense of Maggie is particularly impassioned: ''She's a landlord. She's got courage. She has no pretenses. She is who she is and she's not afraid,'' says Turner. ''Sounds like a man's role, doesn't it?''