Perhaps you should try some spelling variations:
mapping safe » mapping state, mapping space, mapping based
rating case » trading case, rating scale, heating case
rating care » rating scale, framing care, taking care
hua credit » dual credit, a credit, du credit
yang yao » yang yang, wang yan, yang fan
yang yi » yang di, yang xi, yang jui

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: dong ((yang yao) or (yang yi)) hua credit ((rating care) OR (rating case)) mapping safe ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: dong ((yang yao) OR (yang yi)) hua credit ((rating care) OR (rating case)) mapping safe ;.
• The words AND, OR and NOT may confuse the search; try adding quotes: "dong ((yang yao) or (yang yi)) hua credit ((rating care) OR (rating case)) mapping safe ;".
• Adding a wildcard symbol may retrieve word variants: dong ((yang yao) or (yang yi)) hua credit ((rating care) OR (rating case)) mapping safe ;*.