Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
hanh ve » hanh vi, hanh va, hanh kem
luc van » luoc van, luu van, duc van
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, mang may
ve cau » ke cau, ve cac, le cau
va cau » van cau, va cac, va dau
ve cua » le cua, de cua, te cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((nang ma) OR (nang cao)) hoi. hieu ((ve cau) OR (va cau)) luc van hanh ve cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((nang ma) or (nang cao)) hoi. hieu ((ve cau) OR (va cau)) luc van hanh ve cua tre~".
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((nang ma) or (nang cao)) hoi. hieu ((ve cau) OR (va cau)) luc van hanh ve cua tre*.