Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va thanh » gia thanh, va tinh, le thanh
qua cam » qua cham, qua cac, qua ca
cam duc » cam xuc, cao duc, pham duc
san ky » sang ky, van ky, ban ky
dan ky » van ky
nang o » nang co, nang ho, nang ro
di cua » dai cua, doi cua, de cua
cua te » cua tu
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((san ky) or (dan ky)) nang o hoi. hieu qua cam duc ((va thanh) or (ban thanh)) di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((san ky) OR (dan ky)) nang o hoi. hieu qua cam duc ((va thanh) OR (ban thanh)) di cua te.
• Adding a wildcard symbol may retrieve word variants: tu ((san ky) or (dan ky)) nang o hoi. hieu qua cam duc ((va thanh) or (ban thanh)) di cua te*.