  Deuteron breakup processes $p+d\to (NN)_{s,t}+N$ are studied in the
kinematics of backward elastic pd-scattering at law relative momenta of the
NN-pair $k\sim 0-50 MeV/c$ for initial energies $T_0=0.5-2.5 GeV$ in the
framework of the known mechanisms of the $pd\to dp$ process including
rescatterings in the initial and final states. A considerable suppression of
the $\Delta-$ and $N^*-$ isobar excitation mechanisms is found for the
production of the singlet $(NN)_s$-pair. As a result, one nucleon exchange
mechanism can be identified in the cross section and polarization observables
by the node of the half-off-shell NN$(~^1S_0)$-scattering amplitude, $t(q,k)$,
at $q\sim 0.4 $ GeV/c.
