Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
tang ma » tang van
hieu ve » hieu va, hieu van
cac nop » cac hop, cac lop, cac nuoc
dan dai » dat dai, can dai, dan dat
ve cac » va cac, vien cac
nop va » hop va
va dan » ca dan, va dao, va dau
cua te » cua tu

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: tu sach ty ((mang may) OR (tang ma)) hoi. hieu ve cac nop va dan dai cua te~.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((mang may) or (tang ma)) hoi. hieu ve cac nop va dan dai cua te*.