MicroModules:

URLs: How do they work?

The site: operator searches all sites within a specific domain.
Example:site:edu returns results from all urls ending in .edu.

The -site: operator removes one domain from your search.
Example: -site:net eliminates results from all urls ending in .net

The site: operator also allows a search within a specific site. Example: site:imsa.edu returns results from just IMSA.edu

Most domain names should not inspire trust when evaluating a website. Anyone can register for org, net, or com domains.

Reserved domains are somewhat more trustworthy. The content provider must qualify for a reserved domain. Reserved domain names include: gov, mil, edu, museum, aero and coop.