"There is nothing more to add too at the moment," he told Sky Sports News.
"We haven't brought any new faces in but as always we are keen to add to the squad.
"What we are facing is a numbers shortage. There is no way we will be able to survive at our current level if it continues like this.
"It will be impossible to have any improvement this season if we do not improve the numbers greatly.
"We cannot sustain what we did last season, finishing fifth and having a good European run. We could not really sustain it when we were short of players from January onwards last season.
"Now we are more players short than then, so if we are in a worse position there is no way we can achieve again what we did last season. We are trying to make it better and working hard on the current situation."
Moyes insists he has never had it harder since taking charge at Goodison Park.
"This is probably the toughest period I have had as Everton manager, mainly because a lot of my concentration at the moment is not with the players I have here - and they are the most important - but with trying to bring new players in," he said.
"There is no doubt that a lot of our energy is being spent on players we want to sign, and that is not helpful for the team.
"We have come close to making signings. But I believe it shows how much you need big money in this division to attract players.
"You need to do it at the right time and the shutters in the shop are halfway down at the moment with just a week to go.
"The business has changed. There are a lot of people these days with their finger in the pie, it makes things difficult but that is there way things are going these days.
"I am still looking for seven or eight new players at the moment!"