In DocView mode, you can search the file's text for a regular
expression (see Regexps). The interface for searching is inspired
isearch (see Incremental Search).
To begin a search, type C-s (
doc-view-search-backward). This reads a regular
expression using a minibuffer, then echoes the number of matches found
within the document. You can move forward and back among the matches
by typing C-s and C-r. DocView mode has no way to show
the match inside the page image; instead, it displays a tooltip (at
the mouse position) listing all matching lines in the current page.
To force display of this tooltip, type C-t
To start a new search, use the search command with a prefix argument; i.e., C-u C-s for a forward search or C-u C-r for a backward search.