Perhaps you should try some spelling variations:
tranh chuan » trinh chuan, tranh chua, tranh chap
tranh cua » doanh cua, manh cua
nang cong » nang song, dang cong, bang cong
doc hieu » toc thieu, hoc thieu, hoc hien
ho chieu » theo chieu, hoc thieu, doi chieu
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc hieu) or (ho chieu)) xanh - canh ((tranh chuan) OR (tranh cua)) nang cong san toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (ho chieu)) xanh - canh ((tranh chuan) OR (tranh cua)) nang cong san toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hieu) or (ho chieu)) xanh - canh ((tranh chuan) OR (tranh cua)) nang cong san toan cau".
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (ho chieu)) xanh - canh ((tranh chuan) OR (tranh cua)) nang cong san toan cau*.