Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
thanh dai » thanh hai, thanh tai, thanh dat
va thanh » gia thanh, ban thanh, va tinh
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
cau duc » cao duc, cau luc, chu duc
co hai » co dai, co hoi, so hai
va cau » van cau, va cac, va dau
o hai » so hai, o lai, _ hai

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 xang ((o hai) OR (co hai)). hieu va cau duc va thanh dai ((cua triet) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty xang ((o hai) OR (co hai)). hieu va cau duc va thanh dai ((cua triet) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty xang ((o hai) OR (co hai)). hieu va cau duc va thanh dai ((cua triet) or (va triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ty xang ((o hai) OR (co hai)). hieu va cau duc va thanh dai ((cua triet) or (va triet))*.