Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
doanh va » doan va, doanh tai, doanh cua
sach thu » sach thieu, sach tham, cach thuc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
mang xa » lang xa, mang may, dang xay
va cua » va chua, via cua, ca cua
ve cam » ve cham, ve cac, va cam
lo va » lo van, lao va, le 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 thu) OR (sach thue)) mang xa hoi. hieu ve cam ((lo va) or (ly va)) doanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thu) OR (sach thue)) mang xa hoi. hieu ve cam ((lo va) OR (ly va)) doanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach thu) OR (sach thue)) mang xa hoi. hieu ve cam ((lo va) or (ly va)) doanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach thu) OR (sach thue)) mang xa hoi. hieu ve cam ((lo va) or (ly va)) doanh va cua tre*.