Perhaps you should try some spelling variations:
chiet tach » chieu sach
nhieu tang » chieu sang, hieu lang, nhiet nang
hanh trinh » canh tranh, hanh chinh
nhung cong » thong cong, hang cong, nhung don
dung cong » dung trong
trinh va » trinh van, trinh vat, trinh ve
dan toan » van toan, dan than, manh toan
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((chiet tach) or (nhieu tang)) - hanh trinh va ((nhung cong) OR (dung cong)) dan toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((chiet tach) OR (nhieu tang)) - hanh trinh va ((nhung cong) OR (dung cong)) dan toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((chiet tach) or (nhieu tang)) - hanh trinh va ((nhung cong) OR (dung cong)) dan toan tap".
• Adding a wildcard symbol may retrieve word variants: theo ((chiet tach) or (nhieu tang)) - hanh trinh va ((nhung cong) OR (dung cong)) dan toan tap*.