bibtex-search-entries is an interactive compiled Lisp function in `bibtex.el'.

(bibtex-search-entries FIELD REGEXP &optional GLOBAL DISPLAY)

Search BibTeX entries for FIELD matching REGEXP.
REGEXP may be a regexp to search for.
If REGEXP is a function, it is called for each entry with two args,
the buffer positions of beginning and end of entry. Then an entry
is accepted if this function returns non-nil.
If FIELD is an empty string perform search for REGEXP in whole entry.
With GLOBAL non-nil, search in `bibtex-files'. Otherwise the search
is limited to the current buffer.
If DISPLAY is non-nil, display search results in `bibtex-search-buffer'.
When called interactively, DISPLAY is t.
Also, GLOBAL is t if `bibtex-search-entry-globally' is non-nil.
A prefix arg negates the value of `bibtex-search-entry-globally'.
Return alist with elements (KEY FILE ENTRY),
where FILE is the BibTeX file of ENTRY.