Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
cam tuc » cam xuc, cam tu, nam thuc
sang ma » tang ma, nang ma, sang tao
vai dau » va dau, van dau, xvii dau
hieu ve » hieu va
va hanh » van hanh, va thanh, va danh
tu van » tu va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu van ky ((sang ma) or (nang cao)) hoi. ((hieu ve) OR (hieu van)) cam tuc va hanh vai dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu van ky ((sang ma) OR (nang cao)) hoi. ((hieu ve) OR (hieu van)) cam tuc va hanh vai dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu van ky ((sang ma) or (nang cao)) hoi. ((hieu ve) OR (hieu van)) cam tuc va hanh vai dau tren".
• Adding a wildcard symbol may retrieve word variants: tu van ky ((sang ma) or (nang cao)) hoi. ((hieu ve) OR (hieu van)) cam tuc va hanh vai dau tren*.