Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
vat hanh » vat thanh, van hanh, nhat hanh
cua viet » ca viet, hoa viet, cua vat
te sach » toc sach
ky lang » ky dang, ky tang, tay lang
hieu he » hieu ve, hiem he, hieu le
va hanh » van hanh, va thanh, va danh
hai cua » thai cua, dai cua, hoi cua
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: te sach ((ky lang) or (ky nang)) hoa hoc. hieu he nam thuc ((vat hanh) or (va hanh)) hai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ky lang) OR (ky nang)) hoa hoc. hieu he nam thuc ((vat hanh) OR (va hanh)) hai cua viet.
• Adding a wildcard symbol may retrieve word variants: te sach ((ky lang) or (ky nang)) hoa hoc. hieu he nam thuc ((vat hanh) or (va hanh)) hai cua viet*.