Sears, Roebuck & Co., the world's largest retailer, said yesterday that profits from its retail stores fell slightly in the first quarter, but increases by its real estate, insurance and financial services division contributed to an overall 4.4 percent increase in income to more than $223 million compared with the same period of 1984.

Sears Chairman and Chief Executive Officer Edward R. Telling said retail sales for the Chicago-based firm were hurt by a slowdown in the economy and a highly competitive marketplace.

In other earnings reports yesterday:

Bethlehem Steel Co. said first-quarter losses reached $62 million compared with a $55 million loss one year ago, because of operating deficits of $40 million in steel and unspecified losses in coal and iron ore mining.

Unocal Corp., in the midst of a takeover battle, said that its earnings held steady in the first quarter of 1985 as improved results from foreign operations and its geothermal energy business were offset by falling petroleum prices.

The New York Times Co. said its first-quarter profits rose 32 percent from a year ago.

* Sears, Roebuck & Co. said that in the period ended March 31 it earned $223.3 million (60 cents a share) on revenue of $8.8 billion. A year earlier, the corporation earned $213.8 million (60 cents) on revenue of $8.4 billion. Earnings per share were steady despite higher income because more shares were outstanding, Sears said.

Sears said sales from its retail stores fell to $4.94 billion from $4.98 billion, and income from the division fell to $76.5 million from $81.6 million.

The corporation's Allstate Insurance group earned $144.3 million on revenue of $2.46 billion compared with income of $143.5 million and revenue of $2.17 billion a year earlier.

Dean Witter, Sears' financial services group, earned $4.1 million on revenue of $659 million compared with income of $1.5 million and sales of $577 million in 1984.

Coldwell Banker, the corporation's real estate group, had income of $31.5 million on revenue of $184 million. A year earlier, the group earned $24.5 million on revenue of $170 million.

* Bethlehem Steel Co. said greater demand for steel for cars, appliances and other consumer goods translated into a 17 percent boost in its first-quarter steel shipments compared with the 1984 fourth quarter.

"Due to the continued surge of steel mill imports, first-quarter shipments were still less than shipments during the first quarter of 1984, and average prices realized were below fourth-quarter 1984 levels," Bethlehem Chairman Donald H. Trautlein told shareholders in Wilmington, Del., at their annual meeting. The company has its headquarters in Bethlehem, Pa.

* Unocal Corp., the nation's 13th-largest oil company, said it earned $180.7 million in the first quarter, a slight improvement from the $180.1 million reported a year earlier. Earnings per share were unchanged at $1.04. Revenue rose 3.7 percent to $2.8 billion from $2.7 billion.

Unocal currently is opposing a takeover bid by an investor group led by oilman T. Boone Pickens Jr. but did not mention the fight in its financial report.

Fred Hartley, Unocal's chairman, said the first-quarter results reflected increased production of geothermal energy and a higher average sales price.

* The New York Times Co. said its profit rose to $32.3 million (81 cents a share) in the first three months of 1985 from $24.5 million (62 cents) a year earlier.

The results included a nonrecurring, after-tax gain of $2.8 million from the sale of property in New York.

Revenue rose 10 percent to $327.9 million from $297.3 million.

The company's newspaper division, which includes The New York Times and 28 regional newspapers, had an operating profit of $49.6 million in the quarter, up from $41.2 million a year ago, as a result of higher advertising and circulation revenue.