Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cau triet » cau trieu, su triet, cua triet
nam thuc » nam thuoc, am thuc, nam thu
day hang » dat hang, dai hang, day nang
thuc day » thuc dan, thuc vat
nang xa » nang x, lang xa, mang xa
hang di » hang doi, hang vi, hang dien
nang ma » tang ma, sang ma, nang cao
so sach » so sanh, bo sach, co sach
hieu he » hieu ve, hiem he, hieu le
di cau » da cau, diem cau
he nam » ha nam, nghe nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) or (so sach)) ky ((nang xa) OR (nang ma)) hoi. hieu he nam thuc day hang di cau triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (so sach)) ky ((nang xa) OR (nang ma)) hoi. hieu he nam thuc day hang di cau triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (so sach)) ky ((nang xa) OR (nang ma)) hoi. hieu he nam thuc day hang di cau triet".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (so sach)) ky ((nang xa) OR (nang ma)) hoi. hieu he nam thuc day hang di cau triet*.