Perhaps you should try some spelling variations:
trinh vat » trinh van, trinh luat, sinh vat
tong cong » trong cong, cong cong, dung cong
cong manh » cong danh, duong manh, cong thanh
chi sach » chinh sach, chieu sach, co sach
toan cau » toan cao, toan tap, toan tai
toan ban » van ban
doi chi » doi khi

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: doi chi sach - thanh ((tich va) OR (trinh vat)) tong cong manh ((toan cau) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi chi sach - thanh ((tich va) or (trinh vat)) tong cong manh ((toan cau) OR (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: doi chi sach - thanh ((tich va) or (trinh vat)) tong cong manh ((toan cau) OR (toan ban))*.