Perhaps you should try some spelling variations:
postal ratings » postal savings, postal saving, postal rates
ratings risk » patients risk
risk tong » risk among, risk along
tong shui » tong hui, cong shu, gong hui
lang yan » wang yan, wang yang, zhang yan
tying up » taking up, tying _
yang jun » yang jui, pang jun, yang jin

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

• Performing a fuzzy search may retrieve terms with similar spellings: lang yan ((tying up) or (yang jun)) postal ratings risk tong shui ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: lang yan ((tying up) OR (yang jun)) postal ratings risk tong shui ;.
• Adding a wildcard symbol may retrieve word variants: lang yan ((tying up) or (yang jun)) postal ratings risk tong shui ;*.