To do a general search for cases (when you don't know all the case's details) you need to use the LexisNexis CaseBase. Under Catchwords/Summary, enter the words that you want to search; for example, domestic violence.
If you know the full details of a case, use Case Base and enter the case in Case/Article name.
CCH online can be used to do a general search for cases.
Austlii (Australasian Information Institute) can be used to find the full judgement of Australian cases.