Perhaps you should try some spelling variations:
nang mai » nang ma, nang tai, lang mai
va hanh » van hanh, va thanh, va danh
hai cua » thai cua, dai cua, hoi cua
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
va dinh » van dinh, va kinh, va tinh
cao duc » dao duc, cao suc, giao duc
va cao » va cac, va co, va dao
sac ky » cac ky, sai ky
cua su » qua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach y) or (sac ky)) nang mai hoi. hieu va cao duc ((va hanh) or (va dinh)) hai cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach y) OR (sac ky)) nang mai hoi. hieu va cao duc ((va hanh) OR (va dinh)) hai cua su.
• Adding a wildcard symbol may retrieve word variants: tu ((sach y) or (sac ky)) nang mai hoi. hieu va cao duc ((va hanh) or (va dinh)) hai cua su*.