Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hanh trinh » canh tranh, hanh chinh
hoc thien » hoc hien, hoc thieu, hoc thiet
cua thong » cua thuong, cua tong, suat thong
cua khong » hua khong, cua phuong, cua thuong
cong ban » cong bang, cong san, cong tan
phan dau » phan tu, hang dau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thien hach - hanh trinh ((cua thong) OR (cua khong)) cong ban ((phan lap) OR (phan dau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thien hach - hanh trinh ((cua thong) or (cua khong)) cong ban ((phan lap) OR (phan dau))~".
• Adding a wildcard symbol may retrieve word variants: hoc thien hach - hanh trinh ((cua thong) or (cua khong)) cong ban ((phan lap) OR (phan dau))*.