Argentina's military junta struggled again today to resolve deep differences over the country's future government and choose a new president to replace Gen. Leopoldo Galtieri.

As the three-member junta went into session early this evening, each of Argentina's three military services was proposing a different solution, ranging from installing as president a veteran general to naming a civilian, while insisting that the choices of the other services were unacceptable. When the meeting adjourned several hours later, officials said only that the military commanders would meet again Monday, indicating that no final decision had been reached.

High-ranking officials said the junta had hoped to select a president by Monday and end days of feuding and governmental paralysis, but political analysts said the armed forces were split so badly that a quick decision might be impossible.

At stake in a week of infighting among military leaders following Argentina's surrender to Britain on the Falkland Islands have been both the country's policy toward resolving its conflict with Britain and the future of the six-year-old military rule.

High Army leaders resolved earlier this week not to continue military action against Britain following the loss of the Falklands. But Argentina has withheld its formal recognition of an end to hostilities in the South Atlantic, saying Britain must first withdraw its troops from the area, and some military leaders have continued to issue vague warnings of continuing warfare.

The Air Force commander-in-chief, Gen. Basilio Lami Dozo, who is strongly backed by his service in seeking the presidency, told reporters twice today that Argentina "has lost a battle, but has not lost the war" with Britain.

Lami Dozo, who in recent weeks has become the most visible member of the military command while seeking popular support for his political ambitions, also said that Argentina's future foreign policy "should be realistic, very pragmatic, and very nationalistic."

During the fighting in the Falklands, the tall, graying Air Force chief was frequently portrayed as a moderate who urged Galtieri to seek a negotiated settlement with Britain. Asked by reporters during a brief trip to the interior city of Cordoba how he would respond to an offer of the presidency, he replied, "I will assume my responsibility as commander in chief of the Air Force." His comments later were broadcast in Buenos Aires.

Lami Dozo's presidential candidacy has been strongly opposed by the Argentine Army, which has traditionally held the balance of power in political struggles within the military. The Army's top generals have insisted that one of their rank be appointed to take Galtieri's place as president, and reports in Buenos Aires today said that the latest leading candidate was retired Gen. Reynaldo Bignone.

Bignone held the important political post of general secretary of the Army under president Jorge Videla in the late 1970s, and he is considered to have good relations with Argentine political leaders and the press.

These credentials would make Bignone far more acceptable to Argentine civilian leaders than Galtieri's replacement as Army commander in chief, Cristino Nicolaides, who is considered an extreme conservative with a distaste for democracy.

Nicolaides has been mentioned as another leading Army candidate for president, along with as many as a dozen other generals who have all enjoyed brief attention as front runners in Buenos Aires' political circles this week.

Despite widespread expectations that the Army would impose its will on the other services, both Air Force and Navy leaders today continued to openly challenge the Army.

Air Force officers were quoted anonymously in Buenos Aires' leading newspapers as saying their service would not accept another military president from the Army.

The right-wing paper La Nacion also published what amounted to a position statement from a "high active naval official" declaring that the Navy was supporting the naming of a civilian president for "a government of transition."

The naval leader was also quoted as insisting that the Navy and Air Force commands would not yield to growing pressure from the Army's top generals that both Lami Dozo and the Navy commander, Rear Adm. Jorge I. Anaya, be forced to resign for their responsibility with Galtieri for ordering the April 2 invasion of the Falklands.

Much of the infighting within the military has revolved around placing or avoiding national blame for the Falklands loss. Army leaders, who on Thursday forced Galtieri to resign his dual position of commander in chief and president, are anxious that Anaya and Lami Dozo do the same so that the Army will not appear to be the only service culpable for the defeat, political sources said.

Analysts say that policy issues and ideology appear to be of secondary importance in the disputes, although it appears certain that the post-conflict shake-up will result in major changes to the programs pursued by the military government since its seizure of power in 1976.

Lami Dozo told reporters today that the military's conservative economic policies, the chief target of domestic opposition in recent years, "should be corrected" with "improved salaries" for working classes.

A change in Argentina's economic policy from an anti-inflationary, free-market model to a state-directed program of development and market stimulation has been a chief demand of political and labor leaders from the incoming government.

Civilian leaders also are seeking the "transition government" mentioned by the Navy that would allow political parties to share power with the military while democratic elections in a decade are organized.

Civilian leaders have watched the maneuvering among the military forces from a respectful distance, and the general public, which has seen five military presidents during the past 15 months, largely has disregarded it.

In London, the Defense Ministry announced that the 10-man Argentine crew of a naval research station on Thule Island in the South Sandwich chain, about 800 miles southeast of the Falklands, surrendered peacefully to a British invasion force, The Associated Press reported. British helicopter-borne troops landed on the island Saturday and surrounded the unarmed scientists.

The Sunday Times of London reported that Argentina is holding seven members of the Secret Air Service--Britain's equivalent of the U.S. Army's Green Berets--captured on the mainland in mid-May, AP said. The Defense Ministry refused to comment on the report.