Perhaps you should try some spelling variations:
duong trong » dung trong
thien chanh » thien thanh, thien chinh, hien hanh
hanh trinh » canh tranh, hanh chinh
trinh vat » trinh van, trinh luat, sinh vat
vat duong » van duong, mat duong, va duong
trong van » trong cac
van toan » van tuan, van tan, van thanh
toan cao » toan ban, toan tap

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 (thi thanh)) - hanh trinh vat duong trong van toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien chanh) OR (thi thanh)) - hanh trinh vat duong trong van toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc ((thien chanh) or (thi thanh)) - hanh trinh vat duong trong van toan cao*.