Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc anh
van hanh » van thanh, ban hanh, van anh
hoc cac » hoc cao
hieu ve » hieu va, hieu van
cau luc » cau truc, cau phuc
luc van » luoc van, luu van, duc van
hanh ve » hanh vi, hanh va, hanh kem
cua tre » cua te, cuu tre, cua triet
ve cau » ke cau, va cau, ve cac
ve cua » le cua, de cua, te cua

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

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