Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
chieu sach » chinh sach, chiet tach, chieu sang
manh trung » manh tung, thanh trung, manh hung
trung tran » trung tuan, trung thanh, trung tam
tran dung » tran dang, tran hung, tran quang
dung cong » dung trong
cong tap » cuong tap, cong tac, cong tan
tap doan » tap quan
doan cau » toan cau, doan dau, doan cap

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 sach)) - manh trung tran dung cong tap doan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu quang) OR (chieu sach)) - manh trung tran dung cong tap doan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu quang) or (chieu sach)) - manh trung tran dung cong tap doan cau*.