Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, nhieu tang, hieu van
trinh san » trinh han, trinh quan, trinh toan
tinh cua » trinh cua, tinh chat, tranh cua
sinh cua » manh cua, dinh cuu, sinh va
san dau » van dau, san diu, ban dau

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