Concordance, from latin concordare: to concord, to agree, refers to indexes of occurrences of particular phenomena in texts and corpora, e.g. a theme's occurrences in the Bible.
In the Hans Christian Andersen Centre's projekt on Andersen's fairy tales and stories, occurrences of selected motifs in the Andersenian corpus of tales have been quoted and registered. The project is based on systematic readings.
A text search engine does not provide the same; it wouldn't find 'God' if the text says 'The Lord'. Search engines have, of course, other advantages. You may search Jean Hersholt's translations of Andersen's tales at andersen.sdu.dk/vaerk/hersholt/.
Many different issues may be registered in H.C. Andersen's tales, and they may be categorised in several ways.
Lars Bo Jensen has (on 29 April 2005) completed reading the tales and indexing religious motifs.
Jakob H. Zeuthen has analysed animals appearing in the fairy tales, complete with a search engine setup on http://danske-dyr.dk/hca/ (in Danish).