I believe that I am looking for a 1950 or 1980 short fiction story.
"War Against the Yukks", a 1965 novelette by Keith Laumer; first published in Galaxy Magazine, April 1965, available at the Internet Archive.
The story starts out with two men in the jungle looking for an ancient ruin that was reported by other people.
Professor Peter Elton swung his machete half-heartedly at a hanging vine as thick as his wrist; the blade rebounded with a dull chunk. [. . .] "Constable Boyle," he called to the stocky, khaki-clad man whacking at the dense verdure ahead. "Are you sure you know where we're going?"
They find a rock, or pillar, and the scientist uses a new device on it, hoping to carbon date it (this is back when carbon dating was new and strange).
Elton put a protective hand on the case. "The device I have here—which I developed myself—may well revolutionize the whole art of archaeological dating."
"That's a bit over my head, sir," the constable said.
Elton took another swig from the flask and handed it back. "With the chronalyzer—" he patted the case—"I'll be able to establish the ages of stone artifacts which have hitherto defied analysis. You see, the incidence of naturally occurring high-velocity particles on exposed rock surfaces induces sub-microscopic changes in the internal crystalline structure of the material; naturally, when a cut is made in a stone surface by man—"
In the process the strange pillar reveals itself to be a door. Inside is an elevator to a secret room.
The vibration was very perceptible now. The stone was quivering visibly. Elton hastily switched off the chronalyzer. With a loud click! a hairline crack became visible running from top to bottom of the looming cylinder. The crack widened; curved panels were opening out, sliding silently on oiled bearings. A bluish light winked on, revealing an interior chamber lined with fittings of an incomprehensible complexity.
The two men think that it might be a Russian base, or something.
"Ascrabilik ahubarata" an inhuman, metallic voice said from inside the capsule.
"That's not Rooshian, is it, sir?"
"Definitely not Russian," Elton said, backing away.
Turns out that it's a ship. And before they know it they're flying off. The ship's computer takes a moment to reverse their language, and says they're at war with someone.
A sharp buzz cut him off in mid-sentence. He stiffened, his arms jerking out from his sides; a dazed look spread over his face. A pair of bright metal clamps had extended from a receptacle, locked into the constable's head. Elton jumped forward, grabbed his arm, and hauled at him. The buzz stopped abruptly, the clamps retracted. The constable staggered back, his hands to his head.
"Wh-What happened?" he choked. "Felt like my brains was being wrung out like a bar-rag!"
"Mobile Command Center Ten ninety-four, standing by for instructions," a harsh, high-pitched voice with a Middlesex accent said from inside the capsule.
[. . . .]
". . . Grand Fleet annihilated, casualties total," the voice droned on. "Sixth Grand Fleet, casualties ninety-eight percent; surviving units retired to defensive dome at station 92, under Yukk siege—"
The two men land on another planet
"On the surface of the moon Callisto."
and find a dome of energy protecting a colony inhabited solely by women. The women think they're ugly and from another dome. After all, the men don't even have 'bumps.'
The girl holding Elton's arm looked up at him with a reassuring smile; her delicately curved lips were parted, showing even white teeth; her hair looked as soft as angora; here lashes were long and dark. With an effort he kept his eyes from the warm, rounded shape poking against his arm.
"We don't often get visitors from the other domes," she said. "It's kind of exciting, having you here."
"Why did you come?" another asked. "Is it about the fungus competition?"
"Now Nid, the Mother will handle the interrogation."
[. . . .]
"I don't believe I've seen your type before," the Mother said. "Flat-chested, aren't you? And narrow through the hips. You must have a hard time with your babies." She shot Elton a sharp look.
One of the men is about to get it on, you know what I mean, with one of the girls in her apartment, when he finally figures out that none of the women know what men are, calling them by different names. In a flash of insight we learn that the ship they'd used to get into space was run by an all-female crew thousands of years ago and that the girls are a lost colony, ruled by old women, who teach the girls that puberty and sex is the source of 'impure thoughts'.
"Anyway, nine hundred and sixty-five cycles ago, when the war with the Yukks was in its nineteenth cycle, there was a great battle fought between two fleets. Now, in those days there were many among the Girls who were badly tainted with Strange Ways."
Her voice, Elton noticed, had takin on the tone of a pupil reciting lessons. "Because of this, the Girls weren't able to destroy the wicked Yukks, as they deserved. Instead, the Great Mother sent a terrible thing called a Disruptor that caused the machines of the Girls to malfunction, and all of the Girls were killed or captured—except one shipload. The captain was a righteous Mother, and so she and her Girls were spared. They landed here on the World, and set up the Force Domes, and the defensive screens, to keep the Yukks at bay. That's why its our duty to tend the Field Generators, and defend Girlhood, and weed out any traces of . . ." she blushed, ". . . Strange Ways. Not that anybody has any," she added.
[. . . .]
"What about the Yukks?" Elton's voice sounded strained. Tikki undid the last coat button and pulled the garment off him.
"Well, the Yukks are evil beings who tried to enslave all Girlhood, once, long ago, before we were driven out of the Heavenly Garden. They were great big ugly creatures, with hair growing all over their faces, and huge, bony hands—six of them, I think—and whenever they could catch a poor, defenseless Girl, they'd . . ." Tikki swallowed, her face pink. "They'd do Strange Things to her."