Perhaps you should try some spelling variations:
trinh vi » trinh va, trinh ve, trinh viet
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
cac bac » cac bai, cac ban, cac cach
tinh vi » tinh voi, dinh vi, tich vi
tinh va » tich va, trinh van, trinh vat
y nang » ky nang, ly nang, v nang
ve cac » va cac, vien cac
bac va » ban va, bac ha, bao va
thiet » thieu

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x ho. hieu ve cac bac va ((((tinh vi) OR (tinh va))) OR (trinh vi)) va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x ho. hieu ve cac bac va ((((tinh vi) OR (tinh va))) or (trinh vi)) va thiet~".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x ho. hieu ve cac bac va ((((tinh vi) OR (tinh va))) or (trinh vi)) va thiet*.