Influence of scintillations upon individual pulses detection: (a) original dynamic spectra panel, in which pulsar signals (PSR B1133+16) were amplified by scintillations, (b) pulses of the pulsar B1133+16 (DM = 4.84066 pc/cm³) after the dedispersion procedure, in which each point corresponds to the excess of the pulse signal over the noise in the off-pulse part of the period (Ulyanov et al. 2006), (c) pulses of the pulsar B0943+10 (DM = 15.31845 pc/cm³) after the dedispersion procedure. It can be seen that the higher the DM value, the narrower the scintillation-enhanced frequency intervals of pulsars become.