Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
duc manh » suc manh, duc anh, duc minh
cua tre » cua te, cuu tre, cua triet
tai cua » thai cua, tai cuc, tri cua
duc van » duc va, duc tan, duc phan
hieu va » lieu va, hieu qua
ky dang » ky nang, ky danh
va cam » va cham, va cac, va cao
sai ky » sac ky
ha hoi » hoa hoi, ha noi, va hoi
su sai » su tai, su hai, su dai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sai ky dang ((ha hoi) OR (xa hoi)). hieu va cam ((duc van) or (duc manh)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sai ky dang ((ha hoi) OR (xa hoi)). hieu va cam ((duc van) OR (duc manh)) hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sai ky dang ((ha hoi) OR (xa hoi)). hieu va cam ((duc van) or (duc manh)) hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sai ky dang ((ha hoi) OR (xa hoi)). hieu va cam ((duc van) or (duc manh)) hanh tai cua tre*.