Perhaps you should try some spelling variations:
chat hoc » chat hoa, chat thom, cho hoc
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
xang xa » lang xa, mang xa, ang xa
hieu va » lieu va, hieu qua
hieu su » hieu sau, tieu su, hieu so
cua tre » cua te, cuu tre, cua triet
y xang » ty xang
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y xang xa hoi. ((hieu va) or (hieu su)) ((cham h'roi) or (chat hoc)) van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y xang xa hoi. ((hieu va) OR (hieu su)) ((cham h'roi) OR (chat hoc)) van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y xang xa hoi. ((hieu va) or (hieu su)) ((cham h'roi) or (chat hoc)) van hanh vi cua tre*.