Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
doan van » doan va, hoang van, luan van
nay thuc » nam thuc, cay thuc, day thuc
cau treo » cau theo, cau tren, cau triet
long ha » dong ha, cong ha, dong hoa
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
thuc va » thuc vat, thuc dan, thuc day
dan van » dang van, dao van, tan van
va nay » va ngay, va cay

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky ((lang xa) or (long ha)) hoi. hieu va nay thuc va ((dan van) or (doan van)) cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky ((lang xa) OR (long ha)) hoi. hieu va nay thuc va ((dan van) OR (doan van)) cau treo.
• Adding a wildcard symbol may retrieve word variants: doc sach ky ((lang xa) or (long ha)) hoi. hieu va nay thuc va ((dan van) or (doan van)) cau treo*.