Specialized search engines can make searching a little easier and increase the chances of finding what you're for.
If you're for PDF or other document files or eBooks try one of theseDocjax
Docjax searches common document files like Word, Excel and Powerpoint as well as PDF files. PDF files open in the browser (if that's the browser setting), other formats download. Docjax has over 320,577 documents from 3,296 websites. If you're
for a document search minus eBooks, give Docjax a try.Pdf Search Engine
PDFSearchEngine searches PDF, CHM, Word (Doc and Docx), RTF and TXT files. There are 512,727,964 searchable items in the database. No ads, clean interface and the choice of formats make it easier to get results.FreeFullPDF
FreeFullPDF aims to increase the visibility and ease of use of open access scientific journals, theses, posters and patents. All scientific subjects are covered and all content are freely available in PDF format. Search and download free scientific publications on life sciences, health sciences, physics, mathematics, social science & humanities. You can search all the articles, or specific areas; thesis, review, patent, clinical trial, proceeding, curriculum vitae and poster. At the moment, there are more than 80 million PDF files. Results display a thumbnail of each listing.soPDF
soPDF has more than 485,000,000 available PDF files. If you're searching for just PDF files that's the only file format you'll find here. The top three results are ads, and the upgraded website message at the top takes you to the French version of the site.