SINCE THE '50s, when Kitty Wells proved a woman could conquer the country market, country music has produced as many queens as kings. Although women artists are all over the contemporary country charts, they seem to have even less success than the men in resisting Nashville's assembly-line recording process. A half-dozen cases in point:

NICOLETTE LARSEN -- "Say When" (MCA- 5556). Larsen has always had a country bent, even as a Los Angeles pop-rocker, but this is her first full-fledged country outing. If Larsen immediately outstrips much of her female competition, it's partly because of superior material from the likes of Jesse Winchester and Bob McDill. Her strong, sultry delivery along with rollicking instrumentation result in country-rock reminiscent in polish and verve of Rodney Crowell and Rosanne Cash.

DOLLY PARTON -- "Real Love" (RCA AHL1-5414). While nothing earth-shaking, this record represents a strong rebound from her disastrous rock and nostalgia album, "The Great Pretender." Here, Parton's childish soprano and effervescence invigorate a synth- based set of pop tunes. The low point is the title track, another mawkish duet with Kenny Rodgers.

TERRI GIBBS -- "Old Friends" (Warner Bros. 25209-1). Gibbs' rich, bluesy alto is one of the finest female voices in Nashville. While this record's songs don't all suit her gospel- oriented delivery, Gibbs, like Ray Charles, adds emotional depth and drama to everything she touches. There are a few outstanding moments here, such as "Ain't Nobody," where Gibbs can set her piano and voice rocking with soulful panache.

CRYSTAL GAYLE -- "Nobody Wants to Be Alone" (Warner Bros. 25154-1). With the exception of a smoky cover of Billie Holliday's "God Bless the hild," Gayle's latest downplays her torchy blues side in favor of over- arranged, treacly pop. The inclusion of Paul Williams' "Love Does That to Fools" is symptomatic of the glitzy cocktail balladry that dominates here. Nary a pedal steel guitar is heard.

SHELLY WEST -- "Don't Make me Wait on the Moon" (Viva 25189-1). Shelly West has developed a successful solo career to compliment her duets with David Frizzell. On her latest album, she sustains the kind of pleasing marriage of country and pop, of fiddles and strings, that dominates contemporary country radio. Unfortunately, West's voice and the urban cowboy scenarios that clutter up her songs aren't distinctive enough to separate her from the crowd.

SYLVIA -- "One Step Closer" (RCA AHL1- 5413). Sylvia is a successful lightweight pop singer whose vision is to be the next Barbara Mandrell. She's shifted gears this time around by hiring producer Brent Maher to give her the same snappy acoustic arrangements he brought to the Judds. But all those plucky guitars and dobros make her pale voice sound as out of place as a lawyer in a chicken coop.