The model of scattering for a crystal with the disturbed surface layer (DSL) and randomly distributed defects (RDD) is proposed and developed within the framework of dynamical theory of the total integrated reflective power in Bragg-diffraction geometry. Within this model, the crystal is separated on three layers. The first layer is a layer heavily disturbed by the plastic deformation; within it, the diffraction is completely absent. This layer may be detected only due to the X-rays absorption within it. The first layer elastically deforms the second layer. Within it, a length of the scattering coherence is less than the extinction length, and consequently, the scattering within it has a kinematical character. The third layer is the dynamically scattering layer, which contains the RRD. On the base of this model, the new physical effects are revealed at Bragg-diffraction in such crystals, and consequently, the methods are proposed for the unique non-destructive quantitative diagnostics of the nanoscale characteristics of both DSL and RRD.