Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
mang lai » mang lam, mang luoi, dang loai
ke mang » ke nang, ke trang
lai hoi » dai hoi, lai hoa, lai roi
hieu su » hieu sau, tieu su, hieu suat
hieu so » thieu so
chao su » cao su, chao xu, achat su
cua te » cua tu
vi cua » vai cua, di cua
su van » tu van, vu van

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cac) or (tu cach)) ke mang lai hoi. ((hieu su) or (hieu so)) chao su van hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cac) OR (tu cach)) ke mang lai hoi. ((hieu su) OR (hieu so)) chao su van hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: ((tu cac) or (tu cach)) ke mang lai hoi. ((hieu su) or (hieu so)) chao su van hanh vi cua te*.