This website is based on the design principle of accessibility and uses keyboard shortcuts to strengthen the browsing convenience Layout is divided in 4 areas：
The following keys are set as the Access keys ( or speed keys) of this website：
Alt+U：Upper block, containing the links to the services of this site, search box, font size setting and versions of this site.
Alt+C: Main content area shows the content of each page.
Alt+L：Links on the Left area.
Alt+Z：Bottom Link area.