The series has never been available in any format as a complete set and it is not currently available on any streaming services. There is a 10 volume set available if you can find it on Ebay of the most popular titles and also a smaller three volume set.
Here is an excellent Wikipedia article that lists all the episodes that were produced: https://en.wikipedia.org/wiki/Great_Books_(TV_program) . I personally have found episodes of this series to be incredibly enjoyable to watch after having just concluded the reading of a particular book. If nothing else, checking the list on Wikipedia will give you a great idea for books that you probably will want to read eventually if you have not already. They are all must-reads.