Perhaps you should try some spelling variations:
hieu suat » hieu luat, hieu qua
hieu sau » hieu su, tieu su, hieu va
sang lai » sang tai, sang lap, mang lai
va hanh » van hanh, va thanh, va danh
tu sang » thu sang, tu lang, tu quang
lai hoi » dai hoi, lai hoa, lai roi
ky sang » ky nang, ky dang, ky tang
tu san » thu san, tu ban, tu can
vi cua » vai cua, di cua
cua te » cua tu
xu va » xu van, tu va, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sang) or (tu san)) ky sang lai hoi. ((hieu sau) OR (hieu suat)) chao xu va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sang) OR (tu san)) ky sang lai hoi. ((hieu sau) OR (hieu suat)) chao xu va hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sang) or (tu san)) ky sang lai hoi. ((hieu sau) OR (hieu suat)) chao xu va hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sang) or (tu san)) ky sang lai hoi. ((hieu sau) OR (hieu suat)) chao xu va hanh vi cua te*.