Perhaps you should try some spelling variations:
tan hanh » tan thanh, tang hanh, toan hanh
hanh tai » thanh tai, hang tai, han tai
hieu ve » hieu va, hieu van
cam duc » cam xuc, pham duc, nam duoc
cao duc » dao duc, cao suc, giao duc
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
co hai » co dai, co hoi, o hai
cuc cu » cuc du, cu cu, cua cu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky nang ((x hoi) or (co hai)). hieu ve ((cam duc) OR (cao duc)) tan hanh tai cuc cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang ((x hoi) OR (co hai)). hieu ve ((cam duc) OR (cao duc)) tan hanh tai cuc cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang ((x hoi) or (co hai)). hieu ve ((cam duc) OR (cao duc)) tan hanh tai cuc cu".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang ((x hoi) or (co hai)). hieu ve ((cam duc) OR (cao duc)) tan hanh tai cuc cu*.