Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hieu ve » hieu va, hieu van
hanh de » hanh ve, hanh kem
luc van » luoc van, luu van, duc van
cau luc » cau truc, cau phuc
cua tre » cua te, cuu tre, cua triet
sach ty » sach tu, sach thu, xach tay
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky
ve cau » ke cau, va cau, ve cac
de cua » le cua, te cua, dieu cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sac ky) or (((sach ty) OR (sach y)))) nang ma hoi. hieu ve cau luc van hanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sac ky) OR (((sach ty) OR (sach y)))) nang ma hoi. hieu ve cau luc van hanh de cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sac ky) or (((sach ty) OR (sach y)))) nang ma hoi. hieu ve cau luc van hanh de cua tre*".