why my site's pages are not index?

site: (domain name) does not return every page found on a website, it's just a sample of pages. 

There is nothing really to solve, it's just how Google works. 

Indexing issues are there but if you follow internal linking and updating good content your site will be index.

There can be multiple reasons.

To list few:-

• Your website or webpage is new.
• Check robots.txt file. (allow web crawlers)
• Check robots tag (that must be do-follow, Index)

For any queries related seo. we are here to help.

Just my two cents here...

Your robots.txt file is way messed up.  You have cross domain disallows in it.

Let me show you...

User-agent: *
Disallow: /kanoo
Disallow: /sitecode.php
Disallow: /st
Disallow: http://root.ir/post7215.html
Disallow: http://root.ir/thread6078.html
Disallow: http://root.ir/newpostinthread6078.html
Disallow: http://root.ir/thread5444.html
Disallow: http://root.ir/post6571.html

The above on the domain sitecode.ir does nothing for you... you should remove those lines from your robots.txt

In addition your sitemaps are not done correctly. You should have a sitemap of sitemaps.  The way you have it is wrong.

here is what you should be doing.. you life will be simpler and some of your indexing issues will
go away.

The following example shows a sitemap index in XML format that lists two sitemaps:

<?xml version="1.0" encoding="UTF-8"?>
  <sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
    <sitemap>
      <loc>http://www.example.com/sitemap1.xml.gz</loc>
    </sitemap>
    <sitemap>
      <loc>http://www.example.com/sitemap2.xml.gz</loc>
    </sitemap>
  </sitemapindex>

go here to further understand this ...
https://developers.google.com/search/docs/advanced/sitemaps/large-sitemaps

Edited to add
In addition to the above.. some of those urls in your robots.txt are infected and set off my
security software.. Those sites could also have a negative impact on your site.

You will have to cross check proper robots on file as well as coding and generate xml sitemap with complete running URLs and submit sitemap.xml in Google webmaster. Hope, it will work index your website easily.