Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh vai » hanh vi, hanh va, hanh tai
hieu va » lieu va, hieu qua
sang ma » tang ma, sang tao, mang may
vai cau » va cau, van cau, vai cac
nang ma » tang ma, nang cao, mang may
va hanh » van hanh, va thanh, va danh
hieu ve » hieu van
cam tuc » cam xuc, cam tu, nam thuc
tuc va » thuc va, truc va, tuc xa
tu san » thu san, tu ban, tu can
san ky » sang ky, van ky, dan ky

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