Perhaps you should try some spelling variations:
sach tay » xach tay, sach hay, sach nay
tay lang » tai lang, tay tang, tay quang
dang de » dang deo, dung de, dang do
thuc va » thuc vat, thuc dan, thuc day
thue va » thuyet va, thuc vat, thuat va
so sach » so sanh, bo sach, co sach
hieu ve » hieu va, hieu van
ve nam » he nam, va nam, le nam
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 ve nam ((thue va) OR (thuc 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 ve nam ((thue va) OR (thuc va)) dang de cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach tay lang ((xa hoi) or (ha noi)). hieu ve nam ((thue va) OR (thuc va)) dang de cua tu".
• Adding a wildcard symbol may retrieve word variants: so sach tay lang ((xa hoi) or (ha noi)). hieu ve nam ((thue va) OR (thuc va)) dang de cua tu*.