Perhaps you should try some spelling variations:
dang van » hoang van, hang va
hieu cua » hieu qua, dieu cua, bieu cua
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay, lang van
cua nam » cua tam, cua ngan, cua nhan
va doan » va doanh, van doan, va dan
thu va » thuc va, thue va, tu va
va cua » va chua, via cua, ca cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((lang xa) or (dang van)) hoi. hieu cua nam thu va doan va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang xa) OR (dang van)) hoi. hieu cua nam thu va doan va cua te.
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang xa) or (dang van)) hoi. hieu cua nam thu va doan va cua te*.