Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
vat hanh » van hanh, va hanh, nhat hanh
nam thuc » nam thuoc, am thuc, nam thu
lang hoa » hang hoa, lang ha, nang hoa
su viet » so viet
su hien » su kien, su tien, thu hien
hieu he » hieu ve, hiem he, hieu le
hoa hoi » khoa hoi, hoa hoc, hoa doi
ky lang » ky nang, ky dang, ky tang
he nam » ha nam, nghe nam
san ky » sang ky, van ky, dan ky
tu san » thu san, tu ban, tu can

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu san ky lang hoa hoi. hieu he nam thuc ((vat hanh) OR (vat thanh)) ve ((su viet) or (su hien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san ky lang hoa hoi. hieu he nam thuc ((vat hanh) OR (vat thanh)) ve ((su viet) OR (su hien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu san ky lang hoa hoi. hieu he nam thuc ((vat hanh) OR (vat thanh)) ve ((su viet) or (su hien))".
• Adding a wildcard symbol may retrieve word variants: tu san ky lang hoa hoi. hieu he nam thuc ((vat hanh) OR (vat thanh)) ve ((su viet) or (su hien))*.