Police have been scouring woodland for missing student Libby Squire on a sixth day of searches for her.
The 21-year-old, from High Wycombe in Buckinghamshire, went missing in Hull on Thursday.
About 20 officers have been searching the wooded area near Oak Road Playing Fields, near where she was last seen, and a police helicopter was also used.
Her mum Lisa said in a statement: "We'd like to thank everyone who has helped this week in trying to find Libby."
Mrs Squire added: "We have been overwhelmed with people's kindness and support and it's been incredible how all her friends, students at the university, and members of the public have joined together to help us look for her."
She described Libby as a "very sociable person [who] has a really close group of friends stretching back to primary school".
Humberside Police said the force had "received hundreds of calls" from the public as it pursued a number of lines of inquiry.
Detectives think Ms Squire got a taxi at the Welly Club music venue before arriving at her student house at about 23:30 GMT, where her mobile phone was found.
But they do not believe the University of Hull student entered the house and have said her phone "has not provided any further insight as to where she may be or her movements that night".
She was spotted on CCTV 10 minutes later near a bench on Beverley Road, by the junction with Haworth Street, where it is thought a motorist stopped to offer her help.
She is believed to have been in the area for about 30 minutes.
On Tuesday, five officers from the police regional marine unit searched a pond at the playing fields.
Later in the day, about 200 students and staff gathered in the rain at the university to show support for Ms Squire, her family and friends.
The family previously said Ms Squire's disappearance was "very out of character" and they were "broken without her".
Ms Squire, who is 5ft 7in tall and has long dark brown hair, was wearing a black leather jacket, black long-sleeved top and a black denim skirt with lace when she was last seen.