Abstract
The upper boundary of the unambiguous phase-shift analysis as is known, is at 310 MeV. Above the meson production threshold this unambiguity is absent. In the range from 600-650 MeV where the physicists of our Laboratory have worked during recent years the scattering amplitude has been determined ambiguously and not very reliably. In this connection all the experiments for studying nucleon-nucleon scattering being carried out at our Laboratory have two purposes: first, the more accurate determination and improvement of the phase-shift analysis and second, the discrimination of the obtained phase-shift sets for the determination of the most probable set of them. My report is a short survey of some of experiments performed with the above purpose at Dubna in recent years.