Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
chieu sang » chieu sach, chieu xanh, hieu lang
hanh trung » thanh trung, hanh trang, manh trung
trung qua » trung quan, trong qua, trung cua
dung cong » dung trong
cong dang » cong dong, cong dan, cong dung
dang hanh » dang thanh, ban hanh, dang van
qua dung » quang dung, su dung, qua song
hanh ban » thanh ban, hang ban, hanh san

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu quang) or (chieu sang)) - hanh trung qua dung cong dang hanh ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu quang) OR (chieu sang)) - hanh trung qua dung cong dang hanh ban.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu quang) or (chieu sang)) - hanh trung qua dung cong dang hanh ban*.