Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh may » hanh ma, hanh mau, hanh ngay
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, nang ma, sang tao
cam tuc » cam xuc, cam tu, nam thuc
tuc van » thuc van, truc van, tuc va
va hieu » van hieu, va dieu, va hien
va cam » va cham, va cac, va cao
may va » may vi, day va

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 ((mang may) or (sang ma)) hoi. lieu va cam tuc van hanh may va hieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((mang may) OR (sang ma)) hoi. lieu va cam tuc van hanh may va hieu.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((mang may) or (sang ma)) hoi. lieu va cam tuc van hanh may va hieu*.