Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
va triet » va thiet, va trien, ve triet
thanh te » thanh ve, thanh de, thanh le
va thanh » gia thanh, ban thanh, va tinh
cham duc » pham duc, cham soc, pham duy
va cham » va chat, va tham
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty cong » tay cong, te cong, tu cong
hieu va » lieu va, hieu qua
o hoc » co hoc, mo hoc, so hoc
o hoi » co hoi, o hai, o hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty cong ((o hoi) or (o hoc)). hieu va cham duc va thanh te ((va triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty cong ((o hoi) OR (o hoc)). hieu va cham duc va thanh te ((va triet) OR (cua viet))*.