Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
nang ma » tang ma, nang cao, mang may
danh vi » hanh vi, dinh vi, danh di
sang ma » tang ma, sang tao, mang may
hieu va » lieu va, hieu qua
vi cau » va cau, ve cau, di cau
tuc va » thuc va, truc va, tuc xa
su can » su van, su cao, tu can
xuc va » duc va, luc va, xac va
can ky » van ky, dan ky, ban ky
va hai » van hai, va chai, va khai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su can ky ((nang ma) OR (sang ma)) hoi. hieu va hai ((xuc va) or (tuc va)) danh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su can ky ((nang ma) OR (sang ma)) hoi. hieu va hai ((xuc va) OR (tuc va)) danh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su can ky ((nang ma) OR (sang ma)) hoi. hieu va hai ((xuc va) or (tuc va)) danh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: su can ky ((nang ma) OR (sang ma)) hoi. hieu va hai ((xuc va) or (tuc va)) danh vi cau tren*.