Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
nam thuc » nam thuoc, am thuc, nam thu
cau tran » cau tren, chu trang, can tranh
long xa » song xa, long ha, lang xa
ky long » ky cong, sy long, ky trong
hieu va » hieu qua
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
cau tra » ca tra, cau ra, cau truc
va dau » va dao
dau va » dau ve, lau va

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 long xa hoi. ((hieu va) or (lieu va)) nam thuc va dau va ((cau tra) or (cau tran))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky long xa hoi. ((hieu va) OR (lieu va)) nam thuc va dau va ((cau tra) OR (cau tran)).
• Adding a wildcard symbol may retrieve word variants: doc sach ky long xa hoi. ((hieu va) or (lieu va)) nam thuc va dau va ((cau tra) or (cau tran))*.