Perhaps you should try some spelling variations:
hanh trinh » hanh chinh
nhung cong » dung cong, thong cong, hang cong
viet tach » viet sach, viet thanh, chiet tach
viet tech » viet sach
cua nhung » va nhung
cong van » cong vang, cong san, song van
van tai » von tai, van tuan
tai tap » bai tap, tai tao, hai tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: oi ((viet tach) OR (viet tech)) - ((hanh trinh) or (canh tranh)) cua nhung cong van tai tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: oi ((viet tach) OR (viet tech)) - ((hanh trinh) OR (canh tranh)) cua nhung cong van tai tap*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "oi ((viet tach) OR (viet tech)) - ((hanh trinh) or (canh tranh)) cua nhung cong van tai tap*".