Perhaps you should try some spelling variations:
hanh mai » hanh mau, hanh may, hanh tai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
va cham » va chat, va tham
hanh ma » hanh mau, hanh may, hanh va
ma hoi » mai hoi, xa hoi, ma hoa
xuc va » tuc va, luc va, xac va
thiet » thieu

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 ky nang ma hoi. hieu va cham ((xuc va) or (duc va)) ((hanh mai) OR (hanh ma)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. hieu va cham ((xuc va) OR (duc va)) ((hanh mai) OR (hanh ma)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoi. hieu va cham ((xuc va) or (duc va)) ((hanh mai) OR (hanh ma)) va thiet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. hieu va cham ((xuc va) or (duc va)) ((hanh mai) OR (hanh ma)) va thiet*.