The Cabinet Papers (from the National Archives) including:
Use quotes to locate a specific phrase, e.g. "Irish Civil War".
Limit your searches to a specific high level domain such as .edu, .org, .gov, and more, you can use the site: command to accomplish this. An easier way to do this is use Google Advanced Search and then enter preferred doman in the site or domain box.
For example, you only want to search U.S. academic educational sites for something. Limit our search results by typing site:.edu or type .edu in the search box.
Check Purdue OWL's guide on Searching Online.