Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
chet duoc » che duoc, cho duoc, che quoc
tang ma » tang van
hieu va » lieu va, hieu qua
va chet » va chiet, va che, va chat
nang ma » sang ma, nang cao
duoc va » nuoc va, duc va, duoc ma
te sach » toc sach
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua

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