Yes, you can use UNR Libraries' online journals and databases from off-campus.
As long as you start from the libraries' website http://library.unr.edu just find what you want and log in with your NetID when prompted.
However, there is some content in OneSearch that, for off-campus users, will only appear if you are logged in. Web of Science and its citation counts is one example.
For more information on using online resources from off-campus including troubleshooting tips, go here: http://guides.library.unr.edu/offcampusaccess/TOC