Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
trinh cua » trinh luat, trinh quan, trinh luan
trinh van » trinh han, trinh quan, trinh toan
tinh cua » sinh cua, tinh chat, tranh cua
ho hieu » ho chieu, hoi hieu, nho hieu
van dau » van dao, phan 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 - hanh ((tinh cua) OR (trinh cua)) thong cong trinh van dau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - hanh ((tinh cua) OR (trinh cua)) thong cong trinh van dau".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh ((tinh cua) OR (trinh cua)) thong cong trinh van dau*.