Google converts all file types it searches to either HTML or text (unless, of course, they already are in one of these formats). Google searches a variety of file formats including
File Format
Suffix
Description
Adobe Acrobat PDF
pdf
A publishing format commonly used for product manuals and documents of all sorts.
Adobe PostScript
ps
A printing format often used for academic papers.
Hypertext Markup […]
When you don’t find what you’re seeking, consider specifying more precisely what you want by using Google’s Advanced Search feature. Don’t be frightened by the name “Advanced Search”; it’s easy to use, and it allows you to select or exclude pages with more precision than Google’s standard search box. Click on the Advanced Search link […]
For Google tips, tricks, & how Google works, visit Google Guide at www.GoogleGuide.com. Google Guide is neither affiliated with nor endorsed by Google.
By Nancy Blachman and Jerry Peek who aren't Google employees. For permission to copy & create derivative works, visit Google Guide's Creative Commons License webpage.