Perhaps you should try some spelling variations:
hanh trinh » hanh chinh
thuat mach » thuat sach, thuat tach, thuyet mach
thuat tac » thuat tach, thuat tao, thuat tai
dung cong » dung trong
cong vang » cong lang, cong quang, cong ngang
qua dung » quang dung, su dung, qua song
vang van » dang van, tang van, lang van

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((thuat mach) OR (thuat tac)) - ((hanh trinh) OR (canh tranh)) qua dung cong vang van ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((thuat mach) or (thuat tac)) - ((hanh trinh) OR (canh tranh)) qua dung cong vang van ban~".
• Adding a wildcard symbol may retrieve word variants: ho ((thuat mach) or (thuat tac)) - ((hanh trinh) OR (canh tranh)) qua dung cong vang van ban*.