Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hanh trang » thanh trung, hanh trinh, minh trang
hien sach » dien sach, kien sach, thien hach
cong van » cong vang, cong san, song van
van than » van thanh, van thang, van tuan
than ban » thanh ban, toan ban, than man

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien sach - ((hanh trang) or (canh tranh)) va nhung cong van than ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien sach - ((hanh trang) OR (canh tranh)) va nhung cong van than ban.
• Adding a wildcard symbol may retrieve word variants: hoc hien sach - ((hanh trang) or (canh tranh)) va nhung cong van than ban*.