UNC Resources Inc. said yesterday it is getting out of the uranium mining business to concentrate on services, manufacturing and new technologies.

The decision completes a financial turnaround in which UNC has gradually shed its problem businesses, restored its operations to profitability and raised enough cash to expand existing operations and embark on an acquisition program.

The company's remaining businesses include UNC Naval Products, which supplies nuclear reactors and fuel for the Navy's submarines; UNC Technical Products, which manufactures aerospace components; National Automatic Tool Co. Inc., which makes factory machinery; and UNC Nuclear Services, which operates a government-owned nuclear reactor.

"Our withdrawal from the depressed mining industry allows us to concentrate our financial and management resources on expanding the more promising technology and service areas of our business and moving in favorable new directions," said UNC President and Chief Executive Dan A. Colussy.

The Falls Church company plans to make some acquisitions this year and is examining firms in new areas such as biotechnology, telecommunications and computer systems, Colussy said. "We're zeroing in on some very interesting candidates."

UNC also announced fourth-quarter results that include a nonrecurring charge of $152 million, primarily a provision for losses on the disposal of its uranium properties. The provision pulled down 1984 earnings, despite a $171.7 million net gain from litigation settlements earlier in the year.

The company reported a net loss of $122.2 million ($6.90 a share) in 1984, compared with a loss of $13 million ($1) in 1983. Revenue, however, increased to $301 million in 1984 from $260 million the year before, and losses from continuing operations were $3.3 million (16 cents), compared with $11.1 million (86 cents) in 1983.

For the fourth quarter, the company reported a loss of $135 million ($6.18), compared with a loss of $11.8 million (86 cents) in the same period of 1983. Before the extraordinary item, the fourth-quarter loss was $2.2 million (10 cents), compared with $6.8 million (44 cents) in 1983.