Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
hanh trinh » canh tranh, hanh chinh
hien sach » dien sach, kien sach, thien hach
bang cong » bang song, hang cong, dung cong
dang cong » dung cong
van thang » van thanh, van khang, van than
van hang » van khang, van hoang, ban hang

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 trinh thiet ((bang cong) or (dang cong)) ((van hang) OR (van thang)) ca~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien sach - hanh trinh thiet ((bang cong) OR (dang cong)) ((van hang) OR (van thang)) ca.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien sach - hanh trinh thiet ((bang cong) or (dang cong)) ((van hang) OR (van thang)) ca".
• Adding a wildcard symbol may retrieve word variants: hoc hien sach - hanh trinh thiet ((bang cong) or (dang cong)) ((van hang) OR (van thang)) ca*.