Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
thuc dan » thuc hanh, hoc dan, thuc vat
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
kinh va » kinh van, tinh va, sinh va
te sach » toc sach
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc day
van lam » van nam
dang ha » dong ha, dung ha, lang ha
ky dang » ky nang, ky danh

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 dang ha noi. hieu van lam ((thuc va) OR (thuc dan)) kinh va ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dang ha noi. hieu van lam ((thuc va) OR (thuc dan)) kinh va ((cua tre) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dang ha noi. hieu van lam ((thuc va) OR (thuc dan)) kinh va ((cua tre) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: te sach ky dang ha noi. hieu van lam ((thuc va) OR (thuc dan)) kinh va ((cua tre) or (su triet))*.