  Nuclear shadowing corrections to the structure functions of deep inelastic
scattering on intermediate-mass nuclei are calculated at very small values of
Bjorken x and small values of Q^2 (Q^2<5 Gev^2). The two-component approach
developed in previous works of authors for a description of the nucleon
structure functions of deep inelastic scattering is used. It is shown that the
hard component of the nucleon structure functions that arises, in terms of the
colour dipole model, from qq-pairs with a high transverse momentum, is almost
not shadowed. It is shown that a change of the slope of the shadowing curve
with a decrease of x depends, at small values of x, on the relative
contribution of the hard component to the nucleon structure function (this
contribution is a function of x and Q^2) and on a size of gluon saturation
effects. It is shown that an accounting for saturation effects becomes
essential for predictions of shadowing at x<10^-4, depending on a value of Q^2.
Results of numerical calculations of nuclear shadowing for several nuclei are
compared with available data of the E665 and the NMC collaborations.
