Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hieu manh » chieu xanh, hieu nganh, dieu hanh
dung cong » dung trong
hang cong » dang cong, hang nong, bang cong
hoc hieu » hoc thieu, hoc hien, doc hieu
trinh va » trinh van, trinh vat, trinh ve
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: hoc hieu manh - hanh trinh va ((dung cong) or (hang cong)) dan ((toan cau) OR (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu manh - hanh trinh va ((dung cong) OR (hang cong)) dan ((toan cau) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu manh - hanh trinh va ((dung cong) or (hang cong)) dan ((toan cau) OR (toan ban))".
• Adding a wildcard symbol may retrieve word variants: hoc hieu manh - hanh trinh va ((dung cong) or (hang cong)) dan ((toan cau) OR (toan ban))*.