Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach
thuat tach » thuat sach, thuat mach, thuat tac
tranh vat » trinh vat, tranh va, tranh van
cong vang » cong lang, cong quang, cong ngang
khang dau » hang dau, phan dau, xang dau
vat dung » van dung, va dung, viet dung
cong van » cong san, song van, cong tan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoa ((thiet tach) or (thuat tach)) - canh tranh vat dung ((cong van) OR (cong vang)) khang dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoa ((thiet tach) OR (thuat tach)) - canh tranh vat dung ((cong van) OR (cong vang)) khang dau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoa ((thiet tach) or (thuat tach)) - canh tranh vat dung ((cong van) OR (cong vang)) khang dau".
• Adding a wildcard symbol may retrieve word variants: hoa ((thiet tach) or (thuat tach)) - canh tranh vat dung ((cong van) OR (cong vang)) khang dau*.