Perhaps you should try some spelling variations:
vien dat » vien dai, vien da, mien dat
viec dat » vien dai, vien da, viec lam
nuoc van » nuoc va, nuoc san, luoc van
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
cuc tre » duc tre, cua tre, cuu tre
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
o hoa » do hoa, so hoa, o ha

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 sac ky nang ((o hoa) OR (co hoc)). hieu ((vien dat) OR (viec dat)) nuoc van hanh tai cuc tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang ((o hoa) or (co hoc)). hieu ((vien dat) OR (viec dat)) nuoc van hanh tai cuc tre~".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang ((o hoa) or (co hoc)). hieu ((vien dat) OR (viec dat)) nuoc van hanh tai cuc tre*.