Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dau truc » cau truc, dai truc, doan truc
hanh lam » thanh lap, hanh kem, hanh va
cua tre » cua te, cuu tre, dua tren
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
te sach » toc sach
hieu va » lieu va, hieu qua
tang ma » tang van
va dau » va dao

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 y ((tang ma) OR (mang may)) hoi. hieu va dau truc va hanh lam ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y ((tang ma) OR (mang may)) hoi. hieu va dau truc va hanh lam ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y ((tang ma) OR (mang may)) hoi. hieu va dau truc va hanh lam ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: te sach y ((tang ma) OR (mang may)) hoi. hieu va dau truc va hanh lam ((cua tre) or (cua triet))*.