Perhaps you should try some spelling variations:
hoc viet » hoc hien
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
thuc va » thuc vat, thuc dan, thuc day
va dinh » van dinh, va kinh, va tinh
dinh vi » dinh ve, dinh viet, dinh tri
va viet » hoa viet, san viet, mai viet
ve nam » va nam, le nam, te nam
he nam » ha nam, nghe nam
sac ky » cac ky, sai ky
su sac » su sach, su cac, su xac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky sang ma hoa. hieu ((ve nam) OR (he nam)) thuc va dinh vi ((va viet) or (hoc viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky sang ma hoa. hieu ((ve nam) OR (he nam)) thuc va dinh vi ((va viet) OR (hoc viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky sang ma hoa. hieu ((ve nam) OR (he nam)) thuc va dinh vi ((va viet) or (hoc viet))".
• Adding a wildcard symbol may retrieve word variants: su sac ky sang ma hoa. hieu ((ve nam) OR (he nam)) thuc va dinh vi ((va viet) or (hoc viet))*.