hi,
please help us
we had more than 12000 index page in Google ,
but amazingly start to decrease the index , up now,
we have 1000 index page in Google
would you please help us,
if your pages are not being updated with new content, google may stop indexing the pages. especially if the pages are deep in the archives the spider may stop looking that deep.
Do you have a sitemap.xml file on the site, registered and recognized by Google? You can create one or buy a tool at xml-sitemaps.com. The free generator is limited in the number of pages but the other costs $19.99 USD and it pings the search engines every time you run it. Once the app is installed and the sitemap.xml is created go to Google Webmaster Tools to register it.
Google has a system of flitering out pages that aren't updated. One simple way to keep your site updated is by putting a time/date script. Or better yet, update them regularly or add new contents to your site.