NEW YORK, AUG. 6 -- Sales revenue grew modestly in July for the nation's biggest general retailers, as stores attempted to hold down inventories in the face of sluggish consumer spending.

Slow growth in consumer income and high consumer debt have slowed spending for some time, and retailers have been keeping inventories low to prevent the need for clearance sales, analysts said.

But while the lack of clearances and accompanying markdowns has slowed sales growth, it has aided profits by keeping margins high.

"Sales are below planned {levels} generally speaking, but profits are in line or a little above planned," said Jeffrey Edelman, a retailing analyst for the investment firm Drexel Burnham Lambert Inc.

"You can't read too much into the July figures," said Alan Silverman of Evans & Co. "There was probably less promotion than last year. But let's face it, retailing is such a seasonal business. July is a very unimportant clearance month."

Sales figures for major general retailers -- which do not include retailers such as supermarket chains or auto dealers -- are considered a key measure of consumer spending, which accounts for about two-thirds of U.S. economic activity.

Sears,Roebuck & Co., the nation's largest general retailer, reported its July sales rose 2.4 percent from the same month last year. Sales for the 26 weeks ended Aug. 1 were 3.7 percent higher than for the same period in 1986.

K mart Corp. said its July sales jumped 7.2 percent from last year, while sales for the 26 weeks ended July 29 were up 8.2 percent from 1986. Sales for stores open at least one year were up 3.4 percent during the month and 3.9 percent during the 26 week-period.

"Unusually warm weather had a favorable impact on seasonal merchandise sales," said K mart Chairman Bernard M. Fauber, adding that inventory levels continue to be in line with budget.

"Sales were basically good," said Monroe Greenstein, an analyst with Bear Stearns & Co. in New York. "Business would have been better had there been more clearance merchandise available. Retailers held inventories pretty tight."

Greenstein said sales were helped by the "miserable" weather that resulted in strong sales of room air conditioners and other durable goods.

"There wasn't a lot of business available, but the margins on available business was good," Greenstein said.

In addition to a lack of markdowns and sluggish spending by consumers, analysts said, retail sales for the month were hindered by relatively good retail activity earlier in the summer.

"The sales performance reflected the fact that much of the seasonal merchandise was sold in May and June, which had the negative effect of limiting sales gains but, importantly, aided profits," said Jeffrey Feiner, a retailing analyst for Merrill Lynch & Co.

Drexel's Edelman said sales of summer apparel was the strongest area for many retailers during the month of July, while sales of big ticket durable items such as washing machines and refrigerators remained slow