Millions of daily backlinks !!!!

Take a look from google

http://www.google.com/search?hl=en&safe=active&tbo=1&rls=com.microsoft%3 Aen-us&tbs=qdr%3Ad%2Csbd%3A1&q=www.nu.edu.sa+-site%3Awww.nu.edu.sa&btnG=Search&aq=f&aqi=&aql=&oq =&gs_rfai=

and

http://www.google.com/search?q=www.nu.edu.sa+-site:www.nu.edu.sa&hl=en&safe=active&tbo=1&rls=com .microsoft:en-us&ei=yx6uTMi7Gp2N4gb23-2LBg&start=10&sa=N

If you check in any site that appear in the result you wiil not find any link for this site but there is keywords similar to the site domain like NU, SA, SA- and so on.In consequence of this, All pages in that site have high PR between 7 and 4 even if it is with few content.

My questions are:
1-What is the technique ?
2-does it legal with google?

This type search query is not correct. It's actually a KeywordA -keywordB search on google keywordA is www nu edu sa and the keywordB is "site:www.nu.edu.sa" Got the idea? If you want to see real linkers use like this
link:domain.com +Keyword it will give you the related backlinks with the keywords some higher position.

Originally Posted by abumohamed

Take a look from google

http://www.google.com/search?hl=en&safe=active&tbo=1&rls=com.microsoft%3 Aen-us&tbs=qdr%3Ad%2Csbd%3A1&q=www.nu.edu.sa+-site%3Awww.nu.edu.sa&btnG=Search&aq=f&aqi=&aql=&oq =&gs_rfai=

and

http://www.google.com/search?q=www.nu.edu.sa+-site:www.nu.edu.sa&hl=en&safe=active&tbo=1&rls=com .microsoft:en-us&ei=yx6uTMi7Gp2N4gb23-2LBg&start=10&sa=N

If you check in any site that appear in the result you wiil not find any link for this site but there is keywords similar to the site domain like NU, SA, SA- and so on.In consequence of this, All pages in that site have high PR between 7 and 4 even if it is with few content.

My questions are:
1-What is the technique ?
2-does it legal with google?

What type of search query it is?

This is search facilities brings extra data about site. You can see official source here: Search Features and here More search help : Google search basics - Web Search Help
link:sitename.com shows dofollow backlinks for that domain.

If you are looking for good link locations, I don't think Google is the best way to go. The links they display are often far too few to be of relevance. You should either use Yahoo Site Explorer, which has a far more comprehensive list, or OpenSiteExplorer, which lists the links by their weight.