Perhaps you should try some spelling variations:
thanh ve » hanh ve, thanh va, thanh vien
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ve bac » ve bao, ve cac, ve ban
bo van » vo van, so van, do van
x hoi » xa hoi, o hoi, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky nang ((x hoi) OR (x ho)). hieu ve bac bo van ((thanh ve) or (hanh vi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky nang ((x hoi) OR (x ho)). hieu ve bac bo van ((thanh ve) OR (hanh vi)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky nang ((x hoi) OR (x ho)). hieu ve bac bo van ((thanh ve) or (hanh vi)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: te sac ky nang ((x hoi) OR (x ho)). hieu ve bac bo van ((thanh ve) or (hanh vi)) cuu tre*.