Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
anh quang » anh xquang, nhanh quang, tinh quang
dung hang » dung thang, dung khang, dung dang
anh quan » anh tuan, ban quan, anh nhan
toan cao » toan ban, toan tap
va dung » van dung, va duong, vat dung
va toan » van toan, bai toan, tap toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien xanh - ((anh quang) or (anh quan)) va dung hang va toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - ((anh quang) OR (anh quan)) va dung hang va toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - ((anh quang) or (anh quan)) va dung hang va toan cao*.