Have you checked itextsharp out?
http://itextsharp.sourceforge.net/
EDIT:
To elaborate, in the TOC, i saw a section on:
15.3.3: Extracting text with PdfReaderContentParser and PdfTextExtractor
And under PdfReaderContentParser:
http://api.itextpdf.com/com/itextpdf/text/pdf/parser/PdfReaderContentParser.html
there is an option to process the pdf content per page.
So it seems to be a round about way, but you can iterate through each page, searching the content for the word that you want and then return the page that you found it under.