Google Scholar is alternative to Summon for finding scholarly material from many sources at once. It includes scholarly material not indexed by the main Google search engine, such a selection of content from university repositories. Also unlike the main Google search, Scholar does not personalise results.
There are two ways of ensuring Scholar links to SIA databases:
If an article or other document is available via SIA's subscriptions, you will see a link "online @ SIA" on the right of the Google results screen: