Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
su triet » su tien, ve triet
hanh hai » thanh hai, nhanh hai, hang hai
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
te sach » toc sach
hieu he » hieu ve, hiem he, hieu le
hoa hoi » khoa hoi, hoa hoc, hoa doi
ky lang » ky dang, ky tang, tay lang
su viet » so viet
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 hoi. hieu he nam thuc va hanh hai ((su triet) OR (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ky lang) OR (ky nang)) hoa hoi. hieu he nam thuc va hanh hai ((su triet) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ky lang) or (ky nang)) hoa hoi. hieu he nam thuc va hanh hai ((su triet) OR (su viet))".
• Adding a wildcard symbol may retrieve word variants: te sach ((ky lang) or (ky nang)) hoa hoi. hieu he nam thuc va hanh hai ((su triet) OR (su viet))*.