A PDF Search Engine is an Internet tool which crawls and searches  all the pdf documents available on the net and indexes or stores them in their database engine.

The following are the advantages of these PDF Search Engines :

• You can freely search and download various different pdf documents and eBooks based on the keywords.
• These sites can also be used to promote your own ebooks or documents by adding your books with the download url and name and description of the book.
• Instead of searching the books in google,yahoo…etc which redirects to these sites only in the page result,it is better to  save your valuable time by directly searching books here.

Here is the list of best PDF Search Engines:

• PDF Search Engine
• Pdfgeni
• Pdfqueen
• Pdfind
• Pdfse
• Pdf-Search-Online
• Pdfdig
• Pdfone
• Paper-search-engine
• Search-pdf-books
• Pdfxp
• Pdf-searcher
• Pdf Database
• Pdf-search
• Pdf-Rapid4me <credit>
  

If you find any more similar sites , then FEEL FREE to comment here 🙂 . As their is a saying ” A comment a day,keeps the doctor away ” , so comment if you liked it. 🙂 🙂