Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dang xay » dang van, van xay
lang xa » lang ha, lang van
hieu va » lieu va, hieu qua
va doan » va doanh, van doan, va dan
la tren » loai tren, dua tren, dat tren
va nam » van nam, ha nam, va nay
thu va » thuc va, thue va, tu va
va la » va lap, va lam, va lai

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

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