Perhaps you should try some spelling variations:
dang xay » dang van, van xay
dat tren » dat trong, dua tren
tu sach » thu sach, su sach, te sach
lang xa » lang ha, lang van
hieu va » lieu va, hieu qua
va doan » va doanh, van doan, va dan
va nam » van nam, ha nam, va nay
thu va » thuc va, thue va, tu va
va dat » va dao, va dau, va dap

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) OR (dang xay)) hoi. hieu va nam thu va doan va dat tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((lang xa) OR (dang xay)) hoi. hieu va nam thu va doan va dat tren".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((lang xa) OR (dang xay)) hoi. hieu va nam thu va doan va dat tren*.