Use quotation marks to search by a person's name or phrase. This narrows your search to an exact match.
For example:
"arc welding"
"gas tungsten"
Use the site:. command to limit your Google search by domain type.
For example using:
site:.edu will limit your Google search results to an .edu domain.
site:.org will limit your Google search results to an .org domain.
site:.gov will limit your Google search results to a .gov domain.
Combine the site:. command with your keyword search terms in quotes to help you limit your Google search results.