Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
dung dai » duong dai, dung tai, dung dat
van dung » van dong, xay dung, tin dung
cam tuc » cam xuc, cam tu, nam thuc
tuc van » thuc van, truc van, tuc va
sach ty » sach tu, sach thu, xach tay
qua cam » qua cham, qua cac, qua ca
nang o » nang co, nang ho, nang ro
o hoc » co hoc, mo hoc, so hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ty) or (sach y)) nang o hoc. hieu qua cam tuc van dung dai ((cua triet) OR (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach y)) nang o hoc. hieu qua cam tuc van dung dai ((cua triet) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) or (sach y)) nang o hoc. hieu qua cam tuc van dung dai ((cua triet) OR (va triet))".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) or (sach y)) nang o hoc. hieu qua cam tuc van dung dai ((cua triet) OR (va triet))*.