Where did you want your search terms to be highlighted:

  • search results page?
  • Google's cached copy of the page?
  • actual page when you follow a link to that result?

How did you generate the screen shot? Is that what you have now? Add-on?

Re: @jscher2000 :
This extension is now Multi-highlight

I used to be a script for Tampermonkey He singled out the found words yellow. after reinstalling the browser I can not find the name can not remember

By the way, the matches in the cite (green URL) and in the snippet below it are bolded by Google, so it's easy to inject a style rule into the page to highlight those bolded terms.

If you use Stylish / userContent.css:

div.g cite b, 
div.g span.st em {
    background-color: #ff0 !important;
}

If you prefer a userscript:

var r = "div.g cite b, div.g span.st em {background-color: #ff0 !important;}";
var s = document.createElement("style");
s.appendChild(document.createTextNode(r));
document.body.appendChild(s);

But real code would be required to highlight the matching words in the large headline, since Google does not mark those in any way.

You could try this script:

https://openuserjs.org/scripts/jscher2000/Google_SERP_Keyword_Highlighter

It's a bit rough due to various things Google does with its matching (singular/plural, synonyms, etc.).

If you don't actually want all your matches yellow, edit line 20 to

var yellowonly = false;

I didn't build a whole array of colors, so if you have a lot of query terms, a lot of them will be yellow anyway.

It's a start. Someone can take it over and improve on it.

Re: @jscher2000 :
Amazing work!!!

Line 58
if (qa[j].split("=")[0] == "text" && location.hostname == "yandex.ru"){ // Yandex

If the change to nigma.ru
It will have the same effect, For me, this 3 search
Thanks again!!! Hopefully this will be helpful to many. You really helped me.

Oh, you use it with www? That's an important detail because line 62 did not allow for that. Please see the updated version, 0.7.1.