Perhaps you should try some spelling variations:
dau tieng » dau tien, cau tieng, day tieng
thanh hoa » thanh pho
duc manh » suc manh, duc anh, duc minh
duc hanh » duc thanh, duc anh, du hanh
hoa dau » hoa dan, hoa dai, hoa dam
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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: tu sach ky nang ((x hoi) OR (o hoi)). hieu ve cam ((duc hanh) OR (duc manh)) thanh hoa dau tieng~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((x hoi) OR (o hoi)). hieu ve cam ((duc hanh) or (duc manh)) thanh hoa dau tieng~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) OR (o hoi)). hieu ve cam ((duc hanh) or (duc manh)) thanh hoa dau tieng*.