hm, I didn’t know about such request “links;www.xxx.com”
But I understand the difference:
link:http://www.xxx.com shows you sites which point to your site, that is all these sites have a link to your site like that
but
links;http://www.xxx.com shows you sites that have text containing the url of your site, they mayn’t have a link to your site such as in the first result but they have http://www.xxx.com in their pages.