Hechinger Co., the 35-store, do-it-yourself chain based in Landover, cut another notch in the lumber company record books yesterday by posting profit gains of 53 percent for the last quarter of 1982 and 37 percent for the full year.

In a year when many retailers felt the effects of recession, Hechinger's earnings rose to $11.7 million (85 cents a share) from $8.6 million (62 cents) in 1981. Sales increased 15 percent to $241.3 million from $210.6 million.

Fourth-quarter profits were $3.7 million (27 cents), leaping over the $2.4 million (17 cents) reported for the final quarter of 1981.

Results for prior years were restated to reflect Hechinger's 3-for-2 stock split in January, and results benefited from LIFO (last-in, first-out) accounting adjustments, company officials said.

Biospherics Inc.'s fourth-quarter performance allowed the Rockville company to squeeze out earnings of $56,776 (3 cents a share) for 1982, the company reported.

That compares with earnings of $189,110 (10 cents) in 1981. Revenues for the year dropped 18 percent to $5.3 million from $6.4 million.

Biospherics earned $89,316 (5 cents) in the fourth quarter, up slightly from the $87,855 earned in the same period of 1981. Revenues dipped to $1.5 million from $1.8 million.

Officials said cost-cutting measures had produced the earnings, and that Biospherics expects improved performance during 1983. The diversified firm engages in environmental, health and maritime instrumentation, scientific and analytical services and information services.