Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
anh va » hanh va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thi nang x ho. hieu ve cac duc van ((anh viet) or (anh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thi nang x ho. hieu ve cac duc van ((anh viet) OR (anh va)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach thi nang x ho. hieu ve cac duc van ((anh viet) or (anh va)) cua tre*.