Perhaps you should try some spelling variations:
thien chanh » thien thanh, thien chinh, tien thanh
hanh trinh » canh tranh
hien hanh » dieu hanh
trong van » trong cac
van toan » van tuan, van tan, van thanh
toan cao » toan ban, toan tap
he dung » he dong, te dung, nghe dung

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 chanh) or (hien hanh)) - ((hanh trinh) OR (hanh chinh)) he dung trong van toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien chanh) OR (hien hanh)) - ((hanh trinh) OR (hanh chinh)) he dung trong van toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thien chanh) or (hien hanh)) - ((hanh trinh) OR (hanh chinh)) he dung trong van toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thien chanh) or (hien hanh)) - ((hanh trinh) OR (hanh chinh)) he dung trong van toan cao*.