Not all databases will work consistently well with all browsers or versions of browsers, and many require plug-in software to view articles.
Many resources require Internet Explorer 8 or higher and the current version of the Adobe Acrobat Reader (for pdf files) or another plug-in viewer to access all features.
The Firefox plug-in for Zotero on may interfere with the libraries' authentication system. If you encounter problems viewing databases and Zotero is enabled, try disabling the plug-in.
If you are unable to open an article in a PDF format, right-click on the link to the article and select either "Open in New Window" or "Save Target As". If you select "Save Target As", you will be able to save the PDF file to your computer and can open the saved file to view the article.
Removing your browser's cookies and cache can fix common browser-related access issues. Google maintains a site with information on how to do this for the most popular browsers.