Enter a Greek word and press "Find and Parse". A screen will appear showing you all the possible grammatical parsings for the word you have entered. Clicking on the words that are shown will provide you with all the forms of that word occuring in the Greek Old Testament/Greek New Testament.
You can use the % as a wildcard to match any character or set of characters at the end, beginning, or middle of a word. For example γη% would match γη, γην, γης, γηρασκω, γηρας, etc.