Search: politics art site:edu > will return results from educational websites - i.e. www.calarts.edu; www.ucla.edu; www.csun.edu; etc.
You can indicate any domain > site:gov (government); site:org (non-profit), etc.
Search: politics art filetype:pdf > will return only PDFs in your results
You can indicate any type of file
More Google search operators available here
Boolean Searching: AND, OR, NOT
AND - narrows your search: politics AND art > retrieves documents that include politics AND art; both terms in a documents for it to be retrieved.
OR - expands your search: politics OR government > retrieves documents that include EITHER politics OR government. Either term can appear in a document for it to be retrieved. Use OR when you are using synonyms in your search terms.
NOT - narrows your search (politics AND art AND california) NOT baja > will leave out documents that include references to Baja California
Truncation: Finds variant word endings
politic* > Retrieves: politics, politician, political