Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
anh quang » anh xquang, anh quan, nhanh quang
quang va » quang van, quan va, quang ma
va duong » van duong, va tuong, va huong
cong tac » cong ty
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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 va duong ((cong san) or (cong tac)) ((toan cau) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - anh quang va duong ((cong san) OR (cong tac)) ((toan cau) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - anh quang va duong ((cong san) or (cong tac)) ((toan cau) or (toan ban))*.