A 35-person police team searched about 30 square miles of the Niles Canyon and Palomares Canyon areas for Michelle Le starting at around 8 a.m. today. The search ended at 6 p.m.
No body or other evidence was found, according to the Hayward Police Department.
Today's search was the latest of more than a half-dozen searches during the past two weeks.
Le's friends and family members hosted a vigil Thursday night at Mount Eden Park in Hayward with the hope that she is still alive.
The vigil was in response to the Hayward Police Department's reclassification of Le's disappearance to a homicide Monday, organizers said.
Le, 26, has been missing since about 7 p.m. on May 27 from Kaiser Permanente Hayward Medical Center on Sleepy Hollow Avenue.
She told classmates she was headed to Reno after her rotation at the hospital. Le left during a break and never returned.
Investigators said they discovered compelling evidence that points to homicide.
Sgt. Steve Brown said investigators wanted to remain hopeful that Le was alive, but "based on all the evidence, we have the grim possibility that Michelle is dead and we should prepare for the worst."
Those with information about Le's disappearance are asked to call Hayward police at (510) 293-7000.