NEW YORK, FEB. 8 -- Stocks closed higher today, reversing Thursday's downturn and recording an even 100-point rise for the week on hopes that lower interest rates might drag the nation out of recession.

The Dow Jones industrial average closed 20.05 points higher at 2830.69, and advancing issues outnumbered those declining by a ratio of about 3 to 2.

Volume fell to 187.8 million shares but turnover for the week -- 1.3 billion shares -- was the heaviest since 1.4 billion in the week of Oct. 30, 1987. The record volume was in the week of Oct. 23, 1987, when 2.3 billion shares were traded.

"We haven't seen an explosion in breadth and volume like this since 1982," said Kenneth Spence, director of Salomon Brothers Inc.'s technical analysis group.

Hope is growing among investors that the economy may avoid a deep and long recession, analysts said. But some investors may take a more sober view next week.

"Since this has been a tremendous week, people need the weekend to get a better perspective on the market," said Sid Dorr at Charles Schwab & Co.

A consolidation period would allow profit-taking after the market's three-week advance of 322 points since the outbreak of the Persian Gulf War.

Bonds, freed from the uncertainty of this week's massive Treasury auctions, notched sharp gains in late trading. The benchmark 30-year bond was up nearly a full point, pushing its yield down to 7.95 percent from 8.06 percent.

Drug stocks were among the strongest performers. Eli Lilly added 3 1/2 to 77 3/8, Pfizer gained 3 5/8 to 96 5/8, Syntex Corp. rose 2 1/2 to 69 3/8, Merck & Co. increased 2 to 97 1/2, American Home Products picked up 1 to 55 and Johnson & Johnson climbed 7/8 to 77 1/4.

Genetics Institute rose 3 1/4 to 51 3/4. A Shearson Lehman Brothers Inc. analyst reportedly told Shearson's sales force that the resignation of Harry F. Hixson Jr. as president at competitor Amgen is positive for Genetics Institute.

Western Digital fell 1 7/8 to 4 1/2 on investor disappointment over a fourth-quarter operating loss.

Orion Pictures added 1 3/8 to 12 5/8. Wall Street sources said several investors, including Sony Corp., have expressed interest in equity stakes or in an acquisition.

General Motors added 1 3/8 to 12 5/8. Shearson Lehman upgraded its opinion on the stock to buy from sell.

Technology stock gainers included Compaq Computer, up 1 7/8 to 71 3/8; IBM, 1 higher at 129 1/2; Apple Computer, up 2 1/8 to 59 7/8; Cisco Systems, ahead 2 1/8 to 59; and BMC Software, up 2 1/4 to 41 3/4.

Unisys Corp. moved on rumors. The stock advanced 1 1/8 to 4 on volume of more than 5 million shares on talk that the company is considering a restructuring.

Carter Hawley Hale dropped 5/8 to 1 7/8 on fears that it will miss interest payments due on its bonds this month. L.A. Gear fell 1 1/8 to 10 3/8 after reporting that it lost more than expected in the fourth quarter.

The New York Stock Exchange composite index moved up 1.36 points to 196.10, the American Stock Exchange index rose 2.22 to 336.88, the Nasdaq index gained 1.79 to 436.80 and the Standard and Poor's 500 index rose 2.83 to 359.35.