Perhaps you should try some spelling variations:
van thinh » van thanh, van chinh, van minh
va trinh » van trinh, va tinh, lap trinh
cua tre » cua te, cuu tre, cua triet
nam qua » nam quan, nam cua, nam mua
hieu ca » hieu cac, hieu cua, hieu va
di cua » dai cua, doi cua, de cua
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
ca nam » cua nam, cai nam, ha nam
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 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: tu sac ky nang ((x hoi) or (o hoi)). hieu ca nam qua ((va trinh) or (van thinh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang ((x hoi) OR (o hoi)). hieu ca nam qua ((va trinh) OR (van thinh)) di cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang ((x hoi) or (o hoi)). hieu ca nam qua ((va trinh) or (van thinh)) di cua tre*.