Perhaps you should try some spelling variations:
trinh quang » tinh quang, trinh quan, tranh quang
cong thanh » dong thanh, cong trinh, truong thanh
hien xanh » hien hanh, hien nhanh, chieu xanh
trinh qua » trinh quan, trinh cua, trinh luat
cong tan » cong tac, cong san, cong ty
tran cau » tran chau, toan cau, ran cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien xanh - hanh ((trinh qua) or (trinh quang)) dung ((cong tan) OR (cong thanh)) tran cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - hanh ((trinh qua) OR (trinh quang)) dung ((cong tan) OR (cong thanh)) tran cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien xanh - hanh ((trinh qua) or (trinh quang)) dung ((cong tan) OR (cong thanh)) tran cau".
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - hanh ((trinh qua) or (trinh quang)) dung ((cong tan) OR (cong thanh)) tran cau*.