Perhaps you should try some spelling variations:
cua triet » su triet, va triet
cua viet » ca viet, hoa viet, cua vat
chat duc » chat xuc, chat doc, chet duoc
doan vi » doan va, don vi, doan thi
te sach » toc sach
va chat » van chat, va phat, cao chat
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
sach v » sach va, sach y, sach 2
dan vi » don vi, dan va, gan vi
v nang » va nang, vu nang, van nang

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