Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
trinh toan » tinh toan, thanh toan, trinh han
hieu lang » chieu sang, nhieu tang, hieu van
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
cua nhung » va nhung
trinh san » trinh han, trinh quan, trinh luan
tinh cua » trinh cua, sinh cua, tinh chat

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((hieu lang) or (hieu quang)) - hanh tinh cua nhung cong ((trinh san) OR (trinh toan)) dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((hieu lang) OR (hieu quang)) - hanh tinh cua nhung cong ((trinh san) OR (trinh toan)) dau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu lang) or (hieu quang)) - hanh tinh cua nhung cong ((trinh san) OR (trinh toan)) dau".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu lang) or (hieu quang)) - hanh tinh cua nhung cong ((trinh san) OR (trinh toan)) dau*.