it's not the presence of those letters, that makes it hard to find a word in a dictionary
there is a web dictionary of Polish that has plenty of forms of Polish words ( here:
sjp.pl) - the thing is the defintions are in Polish and the various forms of words are not explained grammatically (which grammatical case (case as in declination) or tense or other categories the word forms belong to) - the basic form is just stated -
of course it still can be of some help for learners of Polish
well I tried sjp.pl a bit and well: it's flawed more than I thought