Perhaps you should try some spelling variations:
cua triet » su triet, va triet
cua viet » ca viet, hoa viet, cua vat
van hanh » van thanh, ban hanh, van anh
cham duc » pham duc, cham soc, pham duy
vu cham » va cham, vu kham, tu cham
hanh va » hang va, hanh vi
duc van » duc va, duc tan, duc manh
tu sach » thu sach, su sach, te sach
ty hang » ly hang, ty xang, thi hang
ty tang » tay tang, ty xang, ky tang
hieu vu » hieu va, hieu ve, hieu su
ma hoi » mai hoi, xa hoi, ma 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 tang) or (ty hang)) ma hoi. hieu vu cham duc van hanh va ((cua triet) OR (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty tang) OR (ty hang)) ma hoi. hieu vu cham duc van hanh va ((cua triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty tang) or (ty hang)) ma hoi. hieu vu cham duc van hanh va ((cua triet) OR (cua viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty tang) or (ty hang)) ma hoi. hieu vu cham duc van hanh va ((cua triet) OR (cua viet))*.