While it is possible to find Office documents and PDF ebooks on the web using the filetype search operator of Google, this method has two drawbacks:
1. You need to download the document in order to view the contents as Google, for some reason, doesn’t provide the "View as HTML" function for all documents in search results.
2. The search syntax may sometimes get a bit complex especially when you want to search documents of multiple file extensions in the same query (example: invoice template filetype:doc OR filetype:pdf OR filetype:xls).
Enter DocJax – it’s a new document search engine built on top of search results aggregated from Yahoo and Google. DocJax will simultaneously search for documents of all popular formats (PDF, DOC, XLS and PPT) or you may limit results to any one of these file formats.
Docjax document search engine can understand most search operators including site:, intitle: and inurl: so you can easily filter stuff. As an example, you can case "data structures site:edu" to find papers that are only available on the university websites.
The other advantage of using DocJax over regular web search is inline preview – the search results are neatly integrated with Scribd so you can quickly view the entire contents of any document in the browser itself without having to download the file.
On the downside, DocJax will only look with regular Office file formats (like doc, xls, etc.) though the web search at Google now supports Office 2007 formats as well. Thanks Keisa Williams.