Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
vien cac » vien bach, vien dai, vien da
hanh gia » danh gia, thanh gian, hinh giao
van hanh » van thanh, ban hanh, van anh
gia cua » gian cua, giau cua, gia cuc
duc van » duc va, duc tan, duc manh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ve cac » va cac
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, 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 ky nang ((o hoi) OR (o hai)). hieu ((ve cac) or (vien cac)) duc van hanh gia cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoi) OR (o hai)). hieu ((ve cac) OR (vien cac)) duc van hanh gia cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((o hoi) OR (o hai)). hieu ((ve cac) or (vien cac)) duc van hanh gia cua triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoi) OR (o hai)). hieu ((ve cac) or (vien cac)) duc van hanh gia cua triet*.