Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
tinh doi » trinh doc, trinh do, tinh hoc
su sach » so sach, vu sach
doi cua » dai cua, hoi cua
luc may » truc may, phuc may
cac luc » cau luc, coc luc, cac nuoc
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
ve cac » va cac, vien cac

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

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