Perhaps you should try some spelling variations:
cong thanh » dong thanh, cong trinh, cong tan
tranh vat » trinh vat, tranh va, tranh van
dang cong » dung cong
dat sach » dat khach, nam sach, ban sach
mat sach » mang sach, nam sach, ban sach
vat dang » van dang, vat dung, va dang
hoa chat » hop chat, hoa phan
hoa cac » chon cac

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: theo ((dat sach) OR (mat sach)) - canh tranh vat dang cong thanh ((hoa chat) OR (hoa cac))~.
• Adding a wildcard symbol may retrieve word variants: theo ((dat sach) or (mat sach)) - canh tranh vat dang cong thanh ((hoa chat) or (hoa cac))*.