Available at is followed by the name of one of the libraries in the UO Libraries system. This means that the item is currently available at that location, and applies to physical formats such as print journals, print books, and DVDs. You can go pick up the item (library locations and hours).
If it is at a location that is inconvenient for you, you can select "Request UO Item" to have it delivered to a library near you. You must be logged in to see the "Request UO Item" option.
Checked out from is followed by the name of the one of the libraries in the UO Library system. This means that the item is currently checked out by someone else. If you need the item quickly, click the title of the item and select "Place Summit request (about 5 days)." The UO Library will email you when the item has arrived. For more information on placing a Summit Request. See the tutorial here: http://researchguides.uoregon.edu/requesting-materials/Summit.
Online Access is listed for electronic journals and ebooks that the UO Libraries provide access to online. To get access, click the "Online access" link and select what you would like to do. You may need to be logged in to gain access to the content.
Full text available applies to electronic articles that the UO Libraries provides access to online. Click the "Full text available" link to connect to the full text of the article. You may need to be logged in to gain access to the content.
Check Holdings means the item may be checked out or that it is only available from a Summit library. Click on the "Check holdings" link or the title to get more information, and to request the item. See the tutorial here for requesting items from Summit: http://researchguides.uoregon.edu/requesting-materials/Summit.