No.
x = fzero(fun,x0) tries to find a zero of fun near x0
Notice the singular "a zero".
The same is true for the fzero of the optimization toolbox http://www.mathworks.com/help/toolbox/optim/ug/fzero.html . It is also true for fsolve() from the optimization toolbox.
To get multiple solutions to anything, you need the Global Optimization toolbox, and use one of the MultiStart methods having it report back all of the "local minima" (remember, function()^2 is minimum at its zeros).
There was previously a MATLAB File Exchange contribution which searched for all roots within a given interval, (for a limited class of functions I think), but it appears that the author has removed it.
