Perhaps you should try some spelling variations:
sach tay » xach tay, sach hay, sach nay
tay lang » tai lang, tay tang, tay quang
nam thue » nam thu, nam thuc, lam thue
so sach » so sanh, bo sach, co sach
hieu va » lieu va, hieu qua
thue va » thuc va, thuyet va, thuc vat
va dang » van dang, va nang, va lang
dang de » dang deo, dung de, dang do
va nam » van nam, ha nam, va nay
de cua » le cua, te cua, dieu cua
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach tay lang ((xa hoi) or (ha noi)). hieu va nam thue va dang de cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach tay lang ((xa hoi) OR (ha noi)). hieu va nam thue va dang de cua tu.
• Adding a wildcard symbol may retrieve word variants: so sach tay lang ((xa hoi) or (ha noi)). hieu va nam thue va dang de cua tu*.