You need to already have an NE.se account in order to be able to use this app. If you have access to NE.se via your school/Komvux or via your kommun's public library (for example in Lund), you can create an account here: http://www.ne.se/user/createUser.jsp. Otherwise, you'll need to buy a subscription to NE via their website: http://www.ne.se/.
This is an unofficial app and is not supported by NE Nationalencyklopedin AB.
This app is open source: https://github.com/rabinv/ordboken