Well, a basic search fwd is '/' key (ie /<pattern>), but searching for a '/' require a '\' esc ie
will find first occurrence of '/', measured from the current cursor position(!). The search backwards key is '?'. Note that vi search remembers the last pattern used, so you don't have to repeat the pattern.
'n' repeats the search for next occurrence, in the direction last specified.
However, sounds like you're looking for a search/copy/reuse ? Personally, I'm nearly always in an xterm, so I use the mouse copy/paste, it's easier.
Can you show an example of what you are trying to do?