Perhaps you should try some spelling variations:
khien bang » phien ban, khien dong
hanh trung » thanh trung, hanh trang, manh trung
thanh dang » thanh hang, thanh dan, thanh dung
thanh dong » thanh duong, thanh cong, hanh dong
cong quang » luong quang, thong quang, duong quang
quang tuan » quang thanh, quan luan, quang cua
hien sang » hien trang, chieu sang, thien bang
tuan cau » toan cau, quan cau, tuan cu

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 sang) OR (khien bang)) - hanh trung ((thanh dang) or (thanh dong)) cong quang tuan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sang) OR (khien bang)) - hanh trung ((thanh dang) OR (thanh dong)) cong quang tuan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien sang) OR (khien bang)) - hanh trung ((thanh dang) or (thanh dong)) cong quang tuan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sang) OR (khien bang)) - hanh trung ((thanh dang) or (thanh dong)) cong quang tuan cau*.