Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
van tuan » van quan, van ban, anh tuan
tuan hoi » tan hoi, quang hoi, tuan hoan
thu san » thuy san, thu ban, phu san
vuc van » duc van, luc van, thuc van
hoi cua » hoi chuc
cua tre » cua te, cuu tre, cua triet
san ky » sang ky, van ky, dan ky
nang o » nang co, nang ho, nang ro
ve cac » va cac
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu san ky nang o hoi. hieu ((ve cac) or (vien cac)) vuc van tuan hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu san ky nang o hoi. hieu ((ve cac) OR (vien cac)) vuc van tuan hoi cua tre.
• Adding a wildcard symbol may retrieve word variants: thu san ky nang o hoi. hieu ((ve cac) or (vien cac)) vuc van tuan hoi cua tre*.