Increased production plus higher prices for crude oil and gasoline, gave Phillips Petroleum Co. sharply increased earnings last year.

Philips said Monday it had estimated earnings for 1977 of $517 million ($3.37 a share) on $6.4 billion in revenues. For 1976, earnings were $412 million ($2.69) on revenues of $5.8 billion.

Earnings last year represented a 9.4 per cent return on average total assets.

Improved petroleum prices world-wide were partly responsible for the increases, the company said. Earnings also benefited from increases production of crude oil and natural gas liquids.

"Our production of crude oil increased in both the U.S. and abroad, and our worldwide rpoduction of natural gas liquids was higher," said W. F. Martin, chairman and chief executive officer. "We look forward to further production increases in 1978."

Crude oil production of the company climbed about 5 percent world-wide last year and natural gas liquids production was up 6 percent.

Merrill Lynch & Co., the securities industry giant, said the decline in the stock and fixed-income markets, especially government bonds, resulted in sharply lower earnings for the fourth quarter and full year.

The company's fourth-quarter profits fell to $7.9 million (22 cents) on revenues of $304.5 million against $26.3 million (74 percents) on revenues of $302.6 million a year earlier.

For the full year, Merill's earnings plunged to $43.9 million ($1.25) compared with $106.6 million ($3.01) for 1976. Revenues for the year fell slightly to $1.124 billion from $1.125 billion for 1976.

Sterling Drug Co. Inc., which makes Bayer aspirin, reported a 10.5 percent gain in fourth-quarter earnings and a 37 percent increase in profits for the (32 cents) for the same period a year earlier. Sales increased to $302.001 million from $279.601 million.

For the full year, profits climbed to $85.8 million ($1.43) against $82.8 million ($1.39) 096 billion.

Sterling said the effect of foreign currency fluctuations improved in the fourth quarter compared with the last quarter of 1976.

The company's 1977 results include the operations of Minwax Co. Inc. as of Jan. 1, 1977.

Cox Broadcasting Corp. yesterday reported a record income of $23.6 million ($3.82 a share) for the year ending Dec. 31.

The company - which owns and operates five VHF television stations and five AM and seven FM radio stations - said the figure represents a 20 percent increase over a 1976 profits of $19.7 million ($3.36).

The 1977 income figures sis not included a non-recurring add to earnings of $1.7 million (29 cents), reflecting the cumulative effect of an accounting method change, the announcement said.

Operating revenues for 1977 reached a new high of $186.4 million, up 11 percent from revenues of $167.4 million a year earlier.

Cox Broadcasting President Clifford M. Kirtland Jr. said financial results for last year included Cox Cable, which was merged with Cox Broadcasting effective last year 22.

Comparative 1976 figures were restated to include Cox Cable's profits, the company said.

For the fourth quarter, Cox Broadcasting's earnings rose 28 percent to $7.1 million ($1.08) compared with $5.5 million (95 cents) in 1976.

For the fourth quarter, broadcasting revenues rose 7 percent over the period, with television reporting strong increases in local advertising official said. National TV spot advertising, which had softened during the year, began an upward turn which is continuing into 1978, according to Kirtland.