The nation's civilian unemployment rate dropped from 7.2 to 7.1 percent in April as record sales of new homes and a surge of mortgage refinancings created thousands of jobs across the country, the Labor Department reported yesterday.

The brisk activity in construction and housing helped nonagricultural employment rise by 200,000 jobs last month. The increase in the construction and service industries nearly was offset, however, by continued job losses in the manufacturing and energy industries. Factory jobs are now 240,000 below the peak of the current economic recovery reached in January 1985, and employment in the oil and gas industries has dropped to levels of the late 1970s as a result of falling oil prices.

The Labor Department also reported that import prices, excluding fuel, have risen 3.4 percent during the first quarter, providing some hope that, as foreign goods become more expensive, domestic manufacturers will begin to reap the benefits.

The unemployment report highlighted the continuing growth in service industries and further trouble for manufacturing. "Manufacturing has regained less than 60 percent of the jobs lost during the 1981-1982 recession," said Janet L. Norwood, commissioner of the Bureau of Labor Statistics. "Six of the 21 industries actually have employment below the levels that prevailed at the trough of the recession in November 1982."

Those industries are primary metals, tobacco, textiles, leather, chemicals, and petroleum and coal products, Norwood said.

"Strong over-the-month job gains occurred in construction, and the service-producing sector continued its long-term pattern of job growth," Norwood said. "Mining and factory employment, however, continued to weaken, and the number of unemployed remained above 8 million."

Manufacturing probably won't improve much until the value of the dollar declines further and stays down for a long period of time, some economists said.

Economists also expect a surge in growth later this year resulting from the decline in oil prices, which enhances consumers' income and encourages more spending by consumers and businesses. Falling interest rates also are supposed to help the economy, and last month they led to a surge in jobs in the house construction and financing industries, economists said.

Norwood said she was particularly troubled by the rise in the number of people working part time because they could not find full-time jobs. She said most of the increase resulted from people whose hours were cut back, rather than from those who were laid off from their jobs.

Many economists said that they expect the unemployment rate to decline only slightly this year and fall to about 6.7 percent by December.

"The continuing decline in manufacturing is indicating major industries are still suffering from slow growth and being battered by imports," said Jerry Jasinowski, chief economist for the National Association of Manufacturers. He said the trade picture won't improve dramatically until next year. "It takes a long time to dig your way out of the deep trade hole we've gotten into," he said.

"The service sector is doing very well, and manufacturing and mining are doing terribly," said David Berson, senior economist for Merrill Lynch Economics. "One interesting facet of the report this month is employment in the finance and insurance industries grew very rapidly, a reflection of housing and very strong refinance market."

Employment in the finance, insurance and real estate industries increased by 47,000 jobs last month. "Much of the gain in the finance industry resulted from increased activity among mortgage lenders to meet the demands for new and refinanced home loans," Norwood said.

The unemployment rate that includes members of the Armed Forces stationed in the United States dropped from 7.1 to 7 percent in April. The unemployment rate for men fell from 6.2 to 6 percent, and the rate for women fell from 6.6 to 6.4 percent. The rate for whites dropped from 6.2 to 6.1 percent, while that for blacks rose slightly from 14.7 to 14.8 percent. The rate for Hispanics also rose, from 10.3 to 10.4 percent.