No Streep-like chameleon acts for Sean Young: Like the stars of golden-era Hollywood, she pretty much brings the same persona to film after film. But that persona-a tough cookie waylaid by nervous fragility-is so unusual that she generally intrigues even if the movie disappoints. Here are the Young ones to watch -and avoid. Not included are cameo appearances in Stripes, Dune, and Wall Street.

*JANE AUSTIN IN MANHATTAN (1980) In her first film, a strained affair about rival New York theater troupes intent on staging Austen, Young plays a malleable novice actress. She looks the part. C-

*YOUNG DOCTORS IN LOVE (1982) A stricken intern in a D.O.A. hospital parody. It wants to be another Airplane!, but it never takes off. D

*BLADE RUNNER (1982) Looking like a 21st-century Gibson Girl, she's the android apple of Harrison Ford's eye in Ridley Scott's creepy sci-fi cult epic. A new ''director's cut,'' without the annoying voice-over, has been playing in Los Angeles and will open elsewhere Feb. 14. B+

*BABY...SECRET OF THE LOST LEGEND (1985) A paleontologist who discovers and aids a baby brontosaurus (it looks more like Gumby's mutant brother). C-

*UNDER THE BILTMORE CLOCK (1985) This PBS Fitzgerald adaptation starts wittily, with husband-hunting Young snaring a rich nerd. Then she meets his family, and it turns into bad Jazz Age Twin Peaks. C-

*NO WAY OUT (1987) Her backseat whoopee with Kevin Costner finally made Young a household name. She's only on screen for half of this quick, shivery suspense film-more than enough to give the movie its conscience and the audience a new star. A

*THE BOOST (1988) This feel-bad parable about a couple brought down by cocaine might have been better if the weird vibes between Young and James Woods had made it in front of the cameras. D+

*COUSINS (1989) She hams to a finely tuned fare-thee-well as a two-timing wife (with William Petersen)-- a woman not as smart as she thinks but not as dumb as she looks. B+

*FIRE BIRDS (1990) In this Top Gun ripoff, Young makes you believe her chopper pilot falls for piggy Nicolas Cage -- now that's acting. D-

*A KISS BEFORE DYING (1991) Young plays twins, both at the mercy of murderous mate Matt Dillon. It was a nifty concept in 1956, but the remake gets hornswoggled by a muddled script and botched editing. D