Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hieu xanh » chieu xanh, hieu manh, hieu nganh
trinh vat » trinh van, trinh luat, sinh vat
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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 xanh - hanh trinh vat ((dang cong) or (dung cong)) dan ((toan cau) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh trinh vat ((dang cong) OR (dung cong)) dan ((toan cau) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh trinh vat ((dang cong) or (dung cong)) dan ((toan cau) or (toan ban))*.