Is it possible exctract sinusoids from non periodic signal?
Fourier's theorem say almost any (non-pathological) waveform, periodic or not, can be decomposed into sinusoids (or complex exponentials).  Whether, or how well, those sinusoids correspond to any underlying pseudo-periodic phenomena or not is another issue.

Note that with a DFT, you may need to interpolate a periodic signal between the DFT result bin sinusoids.