Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien danh
thien anh » thien danh, tien anh, thien thanh
hanh tran » hanh trang, thanh tran, hanh tram
tran van » luan van
van dung » van dong, xay dung, tin dung
cong sac » cong sach, cong san, cong suc
cong tac » cong ty
thai cao » tai cao, thoai cac, thuat cao

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: hoc ((thieu xanh) OR (thien anh)) - hanh tran van dung ((cong sac) OR (cong tac)) thai cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu xanh) or (thien anh)) - hanh tran van dung ((cong sac) OR (cong tac)) thai cao~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) or (thien anh)) - hanh tran van dung ((cong sac) OR (cong tac)) thai cao*.