Google is constantly indexing billions of webpages but doesn't attempt to index all the text in every page – that would be too expensive and slow. Instead, they compromise by indexing only the main text (about 90%) of popular sites such as rokuyo.org.
So here's an alternative Search facility, just for this site. It uses a third-party utility "FreeFind" which looks through 100% of the text for all pages on this site.