Perhaps you should try some spelling variations:
thien hach » thien thanh
hanh trinh » hanh chinh
phong cong » phong chong, thong cong, chong cong
cong quang » luong quang, thong quang, duong quang
quang tuan » quang thanh, quan luan, quang cua
hien hanh » dieu hanh
tuan chau » tran chau, chuan chau, thanh chau
va phong » van phong, va phuong, va thong

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thien hach) OR (hien hanh)) - ((canh tranh) or (hanh trinh)) va phong cong quang tuan chau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien hach) OR (hien hanh)) - ((canh tranh) OR (hanh trinh)) va phong cong quang tuan chau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thien hach) OR (hien hanh)) - ((canh tranh) or (hanh trinh)) va phong cong quang tuan chau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thien hach) OR (hien hanh)) - ((canh tranh) or (hanh trinh)) va phong cong quang tuan chau*.