January 21, 1984

President Reagan said Friday that the meeting this week between Secretary of State George P. Shultz and Foreign Minister Andrei A. Gromyko of the Soviet Union ''did not resolve our differences,'' but that it had helped in reducing world tensions. In a statement after meeting with Shultz for 40 minutes at the White House, Mr. Reagan said that the Secretary of State and his Soviet counterpart ''had a full and serious exchange of views on key global questions'' in Stockholm. The President also said that the United States and its Western allies would soon propose a long-awaited package of ''practical and concrete measures'' in Stockholm ''to reduce the risk of surprise attack, or war by accident or misunderstanding.''

Two advocates of Puerto Rican independence, the eighth and ninth in the last year, were found guilty yesterday of criminal contempt of court for refusing to testify before a Federal grand jury investigating nearly 40 unsolved New York City bombings. The F.A.L.N., the group advocating independence for Puerto Rico, has taken responsibility for the blasts. Like seven people convicted, on similar charges in the last year, the latest two found guilty, Michelle Miller and Silvia Baraldini, held that the grand jury was a ''political tool'' of the Government to attack the Puerto Rican independence movement. They vowed they would not ''collaborate.''

Democratic Party leaders today rejected the Rev. Jesse Jackson's demand that they alter rules for choosing delegates to the national convention, rules that he regards as racially discriminatory. In an effort to resolve a long-standing dispute, representatives of Walter F. Mondale had joined Mr. Jackson today in endorsing a compromise. The endorsement represented a major concession, because the Mondale campaign had previously said it considered the party rules inviolate. The rule now requires that a candidate win 20 percent of the primary or caucus vote to receive a proportional share of a state's delegates to the Presidential nominating convention.

The nation's economy grew at an annual rate of 4.5 percent in the fourth quarter of 1983 while inflation remained subdued, the Commerce Department reported today. The pace of growth in the final three months of the year was less than half the recovery's 9.7 percent burst last spring. But the Government called the slowdown encouraging for this year's prospects. The report nevertheless pointed to some trouble spots. High interest rates and the high-valued dollar, factors that many economists attribute to Federal budget deficits, caused a sharp deterioration in the country's trade balance and stunted what otherwise would have been much stronger growth in the overall economy.

Law-enforcement officials report growing evidence of a substantial increase in the number of killers who strike again and again, sometimes traveling from city to city, choosing strangers as victims, then moving on to kill again. They say the killers are extremely difficult to catch because they are often highly intelligent, kill without apparent motive and leave few clues. Most people commonly call such killers mass murderers, but Justice Department officials draw a distinction between ''mass murderers,'' whose multiple killings usually occur in one spot at one time, and ''serial murderers,'' who kill repeatedly over a period of time, often over a wide area. According to a Justice Department study, there have been more than 30 cases in the past decade in which a single killer has murdered at least six people over a period of time, in most cases choosing strangers as the victims. In the past five years alone, the study said, there have been at least 17 men who over time killed a minimum of 10 people each and at least nine who killed 20 people or more. Investigators here said they believe that one man has killed at least 13 girls and young women, and possibly as many as 21, in the past 18 months. The killer is called the ''Green River Killer'' because he dumped the bodies of some of his victims beside a scenic river southeast of here. Law-enforcement officials say there have been isolated examples of such criminals in the past, including ''Jack the Ripper,'' who terrorized prostitutes in 19th century London.