There's a few ways to differentiate from that to change the outcome in your favor as well. For example, you can take away the "inurl:" to get many hits on things
like forum posts or BitTorrent links. (Helpful if you're looking for something rare.)
You can also add the file type you like (such as PDF, CHM, LIT, etc) to get a specialized search. Finally, don't forget to put () or else Google may get confused.
When defining a OR statement, Google expects the () to surround it. For example, you could search for:
- (ebook.DDU | ebook.EEN | ebook.JGT | ebook.LiB | ebook.EAT )
or
- PDF (ebook.DDU | ebook.EEN | ebook.JGT | ebook.LiB | ebook.EAT )
or get fancy with
- (PDF | CHM | LIT | ZIP | RAR | ISO) (ebook.DDU | ebook.EEN | ebook.JGT | ebook.LiB | ebook.EAT)
You can also use "Parent Directory"+ in front of it but don't limit the search to Google, try several engines. [A Markat & Guidoz tut.]
Example: books about Adobe CS2, You could search Google for this (fill google search form):