Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » thien van, lieu va
chat hoc » chat hoa, chat thom, cho hoc
sanh ty » sach ty, canh tay
xang xa » lang xa, mang xa, ang xa
hieu va » lieu va, hieu qua
hoc gia » hoc giao, hoc giai, toc gia
cua tre » cua te, cuu tre, cua triet

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

• If you are trying to use Boolean operators, they must be ALL CAPS: do sanh ty xang xa hoi. ((((hieu ve) OR (hieu van))) OR (hieu va)) chat hoc gia thanh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "do sanh ty xang xa hoi. ((((hieu ve) OR (hieu van))) or (hieu va)) chat hoc gia thanh dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: do sanh ty xang xa hoi. ((((hieu ve) OR (hieu van))) or (hieu va)) chat hoc gia thanh dai cua tre*.