Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
canh trinh » canh tranh, hanh trinh, canh tinh
thang nong » thang long, hang nong, thang trong
hoc thieu » toc thieu, hoc hien
trinh han » trinh quan
tang nong » hang nong, tang dong, tang mong
khoan cam » khoa cam, khoan va, phan cam
khan cap » khan ap, than cap, phan cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thieu xanh - canh trinh han ((thang nong) or (tang nong)) dan ((khan cap) OR (khoan cam))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu xanh - canh trinh han ((thang nong) OR (tang nong)) dan ((khan cap) OR (khoan cam)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu xanh - canh trinh han ((thang nong) or (tang nong)) dan ((khan cap) OR (khoan cam))".
• Adding a wildcard symbol may retrieve word variants: hoc thieu xanh - canh trinh han ((thang nong) or (tang nong)) dan ((khan cap) OR (khoan cam))*.