wildcard searching question

[igoldsmid]

I have a large number of saved web pages, and am looking for pages that contain one or more email addresses.

I created a search as per the attached screen shot. Somewhere around 90% of the hits do in fact contain email addresses, but the rest do not - AND THEY DO NOT CONTAIN ANY OCCURANCES OF "@" EITHER.

I do not understand why this search does not result in 100% success. How can it find documents that don't contain the stated search term?

Is it an erroneous search construction? If not, and it can find docs that don't contain the term, can it miss docs that do contain the term?