Perhaps you should try some spelling variations:
lang khoa » hang khoa, dang khoa, long khoa
nam thuc » nam thuoc, am thuc, nam thu
khoa hoi » khoan hoi, khoa hoc, khoa doi
su triet » su viet, ve triet
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
tu sach » thu sach, su sach, te sach
thuc va » thuc vat, thuc dan, thuc day
sach ky » sac ky, sach y, sach ty
hieu he » hieu ve, hiem he, hieu le
ky lang » ky nang, ky dang, ky tang
su tien » su kien, su hien, tu tieng
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: tu sach ky lang khoa hoi. hieu he nam thuc va hanh ve ((su triet) or (su tien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang khoa hoi. hieu he nam thuc va hanh ve ((su triet) OR (su tien)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang khoa hoi. hieu he nam thuc va hanh ve ((su triet) or (su tien))*.