Mobile version of the site in the search results from a computer, how to change?

Question

Search Engine Optimization

Good afternoon everyone.
Such a problem, there is a site, well optimized, quite well ranked. But at one fine moment, the mobile version of the site on the m.site.com domain began to appear in Google from a computer.
That is, when requesting "Romashka clinic", I see in the output not the main site site.com but m.site.com, tell me how to fix it.

Answer 1

- in the mobile canonical to the main
- in the main canonical to itself
- in the main:

<link rel="alternate" media="only screen and (max-width: 640px)" href="http://m.site.com/мобильная_версия_страницы">

https://developers.google.com/webmasters/mobile-si...