Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
trung cua » truong cua, trung tuan, dung cua
trung cap » truong cao, trung tam
hoc hieu » hoc thieu, hoc hien, doc hieu
san tan » san van, san tay, san ten
van tan » van tuan, van ban, van tai

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 - hanh ((trung cua) OR (trung cap)) nhung cong ((san tan) or (van tan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu quang - hanh ((trung cua) OR (trung cap)) nhung cong ((san tan) OR (van tan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu quang - hanh ((trung cua) OR (trung cap)) nhung cong ((san tan) or (van tan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc hieu quang - hanh ((trung cua) OR (trung cap)) nhung cong ((san tan) or (van tan)) cau*.