Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
hanh de » hanh ve, hanh kem
sach ty » sach y, sach tu, sach thu
su sach » so sach, vu sach
ty nang » ky nang, ty xang, ty hang
ve cac » va cac, vien cac
de cua » le cua, te cua, dieu cua
ve cam » ve cham, va cam, ve cai
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: su sach ty nang ((o hoi) OR (o hai)). hieu ((ve cam) or (ve cac)) thuc day hanh de cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ((o hoi) OR (o hai)). hieu ((ve cam) OR (ve cac)) thuc day hanh de cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ((o hoi) OR (o hai)). hieu ((ve cam) or (ve cac)) thuc day hanh de cua triet".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ((o hoi) OR (o hai)). hieu ((ve cam) or (ve cac)) thuc day hanh de cua triet*.