To search within a website using google, use the site: command (no space after the colon, it is followed immediately by the web address). For example, to search within the Smithsonian website for banjo information, Google: banjo site:si.edu
Use a whole web address to search narrow, use less to search broad. For example:
searches only the Smithsonian Folkways Institute website
searches all Smithsonian institutes and museums
searches all education websites, including colleges, universities, schools etc.