Perhaps you should try some spelling variations:
vien cac » vien dai, vien da, gian cac
thuc day » thuc dan, thuc vat
day hanh » day nhanh, day thanh, dao hanh
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hanh de » hanh ve, hanh kem
ve cam » ve cham, ve cac, va cam
x hoi » xa hoi, o hoi, x ho
de va » de van, te va, ke va

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 ky nang x hoi. hieu ((ve cam) or (((vien cac) OR (vien bach)))) thuc day hanh de va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang x hoi. hieu ((ve cam) OR (((vien cac) OR (vien bach)))) thuc day hanh de va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang x hoi. hieu ((ve cam) or (((vien cac) OR (vien bach)))) thuc day hanh de va triet".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x hoi. hieu ((ve cam) or (((vien cac) OR (vien bach)))) thuc day hanh de va triet*.