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

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)) thuc day hanh ve va thiet~.
• 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)) thuc day hanh ve va thiet.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x hoi. hieu ((ve cam) or (vien cac)) thuc day hanh ve va thiet*.