Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
nhung cong » dung cong, thong cong, hang cong
hoi hieu » hoi phieu, hoi tieu, doi chieu
moi hieu » moi dieu, doi chieu, mot chieu
sinh cua » dinh cuu, sinh va
manh cua » doanh cua, ban cua
quan dau » quan cau, qua dau, quan dac

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

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