As it has throughout the 1970s, the dissident movement in the Soviet Union consists essentially of two parts: those who wish to leave, mainly Jews and ethnic Germans, and those who seek changes from within. Among the most determined are obscue nationalists in remote Soviet republics.

The number of active dissidents has been depleted by arrests and exile to the West of such celebrated figures as Andrei Amalrik and Vladimir Bukovsky, but those that remain are as active as their predecessors although generally less known.

"So what if we are only a few," Yuri Orlov, head of a committee of about 12 dissidents keeping track of Soviet performance in fulfilling the Helsinki accord, remarked some months ago. "Our influence has been widely felt. Take the French Communists who used to go along completely with Soviet methods. Now they are among the Kremlin's sharpest critics in the West. We dissidents had a good deal to do with that. We show the gap between the Kremlin ideal and reality."

On the sensitive subject of emigration, the Soveits - with some justification - say they do not get credit they deserve. Last year about 15,000 Jews and 10,000 ethnic Germans were allowed to emigrate. About 2,500 people were given exit visas to th United States. Still there are several thousand who have increased lately, according to Jews who say they are keeping track.