Perhaps you should try some spelling variations:
tinh hoi » trinh hoi, tinh hoc, tinh hai
van lam » van nam
hoi cua » hoi chuc
va tinh » may tinh
cua tre » cua te, cuu tre, cua triet
van cam » van nam, van cau, van dam
dai hoi » dai hoc, dai hai, dai moi
mai hoi » mai khoi, lai hoi, mai doi
sac ky » cac ky, sai ky
te sac » te sach, te cac, te san

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 ((mai hoi) or (dai hoi)). hieu ((van cam) OR (van lam)) duc va tinh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky nang ((mai hoi) OR (dai hoi)). hieu ((van cam) OR (van lam)) duc va tinh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky nang ((mai hoi) or (dai hoi)). hieu ((van cam) OR (van lam)) duc va tinh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: te sac ky nang ((mai hoi) or (dai hoi)). hieu ((van cam) OR (van lam)) duc va tinh hoi cua tre*.