  The properties of dense nuclear matter under extreme conditions are a subject
of the large experimental activities worldwide. Heavy-ion collision experiments
are the agenda item at RHIC, LHC, FAIR, and NICA facilities. Meanwhile, a
complementary approach to the heavy-ion collision researches devoted to
investigation of phase transitions in few-nucleon systems has not been
discussed. In this paper, we try to fill up the gap. It is shown that signals
of the phase transition of deuteron into 6-q bag as well as signs of formation
of the pion Bose condensate in compressed two-nucleon systems might be already
observed in deuteron-deuteron collisions.
