Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
hoc thieu » toc thieu, hoc hien
hanh tran » hanh trang, thanh tran, hanh tram
tran van » luan van
van dung » van dong, xay dung, tin dung
ty thanh » ta thanh, tu thanh, te thanh
ty than » te than, tu than, thuy than

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: hoc thieu xanh - hanh tran van dung trong ((ty than) OR (ty thanh)) cao~.
• Adding a wildcard symbol may retrieve word variants: hoc thieu xanh - hanh tran van dung trong ((ty than) or (ty thanh)) cao*.