Perhaps you should try some spelling variations:
trinh toan » tinh toan, thanh toan, trinh han
trinh quan » tinh quang, trinh luat, trinh han
nhung cong » dung cong, thong cong, hang cong
hoc thieu » toc thieu, hoc hien
cong than » cong thanh, cong thang, cong tan
than phan » thanh phan, toan phan, thanh pham
ho chieu » theo chieu, doi chieu, mot chieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((ho chieu) OR (hoc thieu)) xanh - canh ((trinh toan) or (trinh quan)) nhung cong than phan tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (hoc thieu)) xanh - canh ((trinh toan) OR (trinh quan)) nhung cong than phan tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) OR (hoc thieu)) xanh - canh ((trinh toan) or (trinh quan)) nhung cong than phan tu".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) OR (hoc thieu)) xanh - canh ((trinh toan) or (trinh quan)) nhung cong than phan tu*.