Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh ki » hanh vi, hanh ky, hanh kien
xuc van » duc van, luc van, vuc van
sach vu » sach va, sach uu, sach xu
so viet » hoc viet
nang ma » tang ma, sang ma, nang cao
sach tu » sach thu, cach tu, sach ty
ma hoi » mai hoi, xa hoi, ma hoa
va cao » va cac, va co, va dao
va cam » va cham, va cac, va cai
ki so » khi so, ka so, ki su

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

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