Perhaps you should try some spelling variations:
cac thoi » cac toi, cac hop, cac tro
sach thu » sach thue, sach tham, cach thuc
doan thi » dan thi, doanh tai, hoang thi
doan vi » doan va, don vi, doan van
thoi va » hoi va, thai va, tho va
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
cuu tre » cua tre, cau tren, cau treo
ve cac » va cac, vien cac

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 thu) OR (sach thieu)) lang xa hoi. hieu ve cac thoi va ((doan vi) or (doan thi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thu) OR (sach thieu)) lang xa hoi. hieu ve cac thoi va ((doan vi) OR (doan thi)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach thu) OR (sach thieu)) lang xa hoi. hieu ve cac thoi va ((doan vi) or (doan thi)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach thu) OR (sach thieu)) lang xa hoi. hieu ve cac thoi va ((doan vi) or (doan thi)) cuu tre*.