Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
qua pham » quan pham, qua cham, qua phan
quy pham » su pham, quy chau, my pham
tan tuan » tran tuan, than tuan, van tuan
tuan dai » toan dai, tuan tai, quang dai
su sach » so sach, vu sach
nang o » nang co, nang ho, nang ro
cua te » cua tu
o hoi » co hoi, o hoc, o hai

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 o hoi. hieu ((qua pham) OR (quy pham)) duc tan tuan dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (hoc sach)) ky nang o hoi. hieu ((qua pham) OR (quy pham)) duc tan tuan dai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (hoc sach)) ky nang o hoi. hieu ((qua pham) OR (quy pham)) duc tan tuan dai cua te".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (hoc sach)) ky nang o hoi. hieu ((qua pham) OR (quy pham)) duc tan tuan dai cua te*.