Perhaps you should try some spelling variations:
thiet tinh » thien tinh, thuyet tinh, chieu tinh
hanh trinh » hanh chinh
nhung cong » dung cong, thong cong, hang cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
cong dan » cong san, cong tan, huong dan
than cau » phan cau, than cap, thanh chau
toan cau » 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 thiet tinh - ((hanh trinh) or (canh tranh)) va nhung cong dan ((than cau) or (toan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tinh - ((hanh trinh) OR (canh tranh)) va nhung cong dan ((than cau) OR (toan cau)).
• Adding a wildcard symbol may retrieve word variants: hoc thiet tinh - ((hanh trinh) or (canh tranh)) va nhung cong dan ((than cau) or (toan cau))*.