Pressure is mounting on Solskjaer to make January signings after Wednesday's 2-0 home defeat by Burnley.
It was a second straight Premier League loss and the players were jeered.
"We've had one proper transfer window and we're trying to do something now," said Solskjaer, who took over - initially on an interim basis - in December 2018.
"Jurgen Klopp spent four years building his team and they're doing well now.
"It's not going be a quick fix - eight or 10 players in the transfer window.
"We can't react to all the noise outside. There'll be criticism - you've got to take it, you've got to be stronger mentally.
"I am, the club is. The staff are very strong mentally and we're sticking to what we believe in. I've got full faith."