Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
va thanh » ban thanh, va tinh, le thanh
lam cua » nam cua, lam chat
cam duc » cam xuc, cao duc, pham duc
vu sach » vu bach, su sach, vu khach
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
ve cam » ve cham, ve cac, va cam
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: vu sach ky nang ((o hoi) or (o hoc)). hieu ve cam duc ((va thanh) OR (gia thanh)) lam cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang ((o hoi) OR (o hoc)). hieu ve cam duc ((va thanh) OR (gia thanh)) lam cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang ((o hoi) or (o hoc)). hieu ve cam duc ((va thanh) OR (gia thanh)) lam cua triet".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang ((o hoi) or (o hoc)). hieu ve cam duc ((va thanh) OR (gia thanh)) lam cua triet*.