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：
- 1. the main menu zone at the top.
- 2. the content zone at the center
- 3. the menu zone on the left side
- 4. the related information zone at the bottom
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. If your browser is Firefox, Press Shift + Alt + Key to jump. For example, press "Shift + Alt + C" to jump to the center of the page.