Perhaps you should try some spelling variations:
cac thoi » cac toi, cac hop, cac tro
doan thi » dan thi, doanh tai, hoang thi
tu sach » thu sach, su sach, te sach
cac thu » cach thuc
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
y lang » o lang, _ lang, tay lang
dan vi » doan vi, don vi, dan 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 y lang xa hoi. hieu ve ((cac thu) or (cac thoi)) va ((dan vi) or (doan thi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y lang xa hoi. hieu ve ((cac thu) OR (cac thoi)) va ((dan vi) OR (doan thi)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y lang xa hoi. hieu ve ((cac thu) or (cac thoi)) va ((dan vi) or (doan thi)) cua tre*.