Depending on what you define as "good"; anyway, you could try one of the scalers.

Thank you for interest you to my problem.
I do connai nothing to back when I say "good", I mean that in window mode resolution is good (that of my office I think) but in fullscreen mode, it's horrible, you can see all the pixels.
I do not know what to change or where. 😕

DOSBox will play at the same resolution the older games played. If you play Syndicate, it will run at 640x480; X-Quest 2 will run at 320x200 and so. Few games could change the resolucion (like Duke Nukem 3D or Shadow Warrior).

If you put DOSBox at high resolutions, it will scale the pixels. By default it will produce square big pixels, but you can change that in dosbox.ini, in the scaler line.

Thanks Zub, I understand. 😀
What should set as a value (sorry, I begin)?
For information, the game is the flight simulator TORNADO from Digital Integration 1993

# scaler: Scaler used to enlarge/enhance low resolution modes. If 'forced' is appended,
# then the scaler will be used even if the result might not be desired.
# Possible values: none, normal2x, normal3x, advmame2x, advmame3x, advinterp2x, advinterp3x, hq2x, hq3x, 2xsai, super2xsai, supereagle, tv2x, tv3x, rgb2x, rgb3x, scan2x, scan3x.

The possible values are listed...well...under possible values; the one you choose depends on personal preference (and processing power...), I, for example, like hq2x.

Thanks bloodbat,I will try that. 😀

Thanks all, all works fine now. 😁