To find the full-text of a particular patent or to discover whether a patent exists, various sources are available:
South Australian sources for patents
The State Library of South Australia has a guide on searching for patents.
Can't get hold of a parent?
If you cannot find a patent elsewhere, try the Library's Document Delivery service or IP Australia. In order for a patent to be tracked down you will usually need to provide information such as patent country, patent number, date and author.