The floodgap and forthworks servers have decent gopher search
services [0][1]. Unfortunately, they do not do full-text search. You
can help make the search more useful by making your filenames and
selectors more descriptive. So, for example, say you create a
document on Linux security. Instead of creating 'sec.txt' name it
'sysadmin_tips_for_linux_system_security.txt'. Then you will see
your document in searches for those component words. If you use a
gophermap, create some nicely descriptive display text, something
like 'Linux Security Tips for Sysadmins'.

Here is a concrete example - I posted the Edgar Rice Burroughs
Barsoom novels on my gopher site. The selector is as follows:

/users/slugmax/docs/books/barsoom_stories_burroughs

and in my gophermap, the descripton is this:

Edgar Rice Burrough's Barsoom series in glorious text

You can find the novels by searching Veronica-2 for 'barsoom' or
'burroughs', or even 'glorious':

 *** Search terms: glorious ***
 First 30 selectors displayed (page 1).
 Results sorted by apparent relevance.
 5 total matches.

   (?)  [2]Enter new search keywords
 (FILE) [3]Folders/directories are least accurate! (and other notes)

 (FILE) [4]Refining your query

      ------------------------------------------------------------

 (DIR) [5]Edgar Rice Burrough's Barsoom series in glorious text
 gopher://sdf.org:70/1/users/slugmax/docs/books/barsoom_stories_burroughs
...

[0] gopher://gopher.floodgap.com/1/v2
[1] gopher://forthworks.com/1/contrition