A Georgetown University Hospital nurse was charged with robbing a shop at Tysons Corner last night after threatening a clerk with a long butcher knife. The holdup was similar to a series of robberies in the last week that police said they believed were committed by the same well-dressed young woman armed with a knife.

The suspect, Pamela Sue Dodd, 25, of 6001 Arlington Blvd., Falls Church, an intensive-care nurse at Georgetown, was being held without bond last night at Fairfax County Jail.

Police said they are continuing to investigate five other similar robberies and an attempted robbery committed since last Thursday along the Rte. 7 corridor between Tysons Corner and Seven Corners.

Police said Dodd was arrested about 9:15 p.m., shortly after the robbery of Timothy's Coffee of the World specialty shop. A few minutes earlier, police said. A shopping center security guard had noticed a woman who matched the description of the suspect in the eariler robberies "acting suspicicous" outside the shop, and summoned a uniformed county police officer.

As the guard and the officer approached the shop, officials said, they heard a scream from inside, and immediately afterward encountered a woman running out the front door with a knife in one and cash in the other.

"She ran right into the officer's arms," said police spokesman Warren Carmichael. He said the officer disarmed the woman and recovered the cash without a struggle.

Georgetown University Hospital officials confirmed that the suspect was employed there.