Perhaps you should try some spelling variations:
trinh quan » trinh luat, trinh han
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
trinh cua » tinh cua, trinh luat, trinh luan
doi hieu » doi chieu, doc hieu, doi hien
cong van » cong vang, cong san, song van
van toan » van tuan, van tan, van thanh
toan cau » toan cao, toan ban, toan tap

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: doi hieu lang - hanh ((trinh cua) OR (((trinh quan) OR (tinh quang)))) nhung cong van toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi hieu lang - hanh ((trinh cua) or (((trinh quan) OR (tinh quang)))) nhung cong van toan cau~".
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - hanh ((trinh cua) or (((trinh quan) OR (tinh quang)))) nhung cong van toan cau*.