Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
artĭfĭcĭālis, e, adj. [artificium], of or belonging to art, artificial, according to the rules of art (perh. only in Quint.): probationes, Quint. 5, 1, 1; so id. 5, 9, 1; 12, 8, 19: ratio, id. 6, 4, 4.
Once subst.: artĭfĭ-cĭālia, ium, n., things conformable to the rules of art, Quint. 1, 8, 14.
Adv.: artĭ-fĭcĭālĭter, according to art (opp. inartificialiter): se gerere, Quint. 2, 17, 42.