Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
sach thi » sach thu, sach tai, sach thieu
thi hang » thi hanh, thi nang, thi hong
viec cac » vien cac, viec cua, viec lam
thu tuan » chu tuan, thu trang, thu thuat
te sach » toc sach
cho hoc » khoa hoc
cac thu » cach thuc, cac thoi
anh vi » hanh vi, anh va, anh ve
vi sua » va sua, vi su, vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach thi hang ((cho hoc) or (co hoc)). hieu viec cac thu tuan anh vi sua (chua* or cua*)~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach thi hang ((cho hoc) OR (co hoc)). hieu viec cac thu tuan anh vi sua (chua* OR cua*).
• Adding a wildcard symbol may retrieve word variants: te sach thi hang ((cho hoc) or (co hoc)). hieu viec cac thu tuan anh vi sua (chua* or cua*)*.