Real Sociedad striker Umar Sadiq and Bournemouth fullback Max Aarons have both arrived on-loan so far in January.
Corona said: "I haven't heard the coach ask for reinforcements.
"What he has said is that we are going to work until January to improve the squad. We will try until the last day. With the 25 slots occupied, there will have to be movements if we want to sign players.
"We have received calls about some of our players.
"The first half of the season is obviously not positive and we believe that there are circumstances that have marked the course of the season for us. We are fully confident that we will improve and that the details, which sometimes fall on one side, will fall on our side.
"There is a huge commitment in the group to achieve the objective and we find strength where there is none. We have a lot of faith that we will achieve it. Our performance should have been better. I think that there will be at least three teams below us at the end of the season."