[R] Problem about plot scale

[yk]

There are 4 sets of array, each have 2 dimension data:x,y.
And these data comes from bkde.
I tried to plot them in one figure, but details of some lines, like
peak and where it locate, have diminished since one set of array have
fairly high y value.And another array have lots of y value near zero,
like 1e-20, 1e-10, like a long tail, while the highest y value of
these arrays is 1e-4.
Does R have the function to cut some range of y value? The
corresponding function in sigmaplot is break in which we could define
break range to omit some meanless range of y value.