Perhaps you should try some spelling variations:
danh vai » danh sai, danh va, doanh van
su sach » so sach, vu sach
sach le » cach le, sach de, sach lo
le tang » le quang, le trung, le thanh
tang xa » trang xa, tang ma, lang xa
hieu ve » hieu va, hieu van
cao suc » cao su
cao duc » dao duc, giao duc, tao duoc
va danh » va dinh, va dan, va hanh
vai va » mai va, dai va, hai va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach le tang xa hoi. hieu ve ((cao suc) or (cao duc)) va danh vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach le tang xa hoi. hieu ve ((cao suc) OR (cao duc)) va danh vai va thiet.
• Adding a wildcard symbol may retrieve word variants: su sach le tang xa hoi. hieu ve ((cao suc) or (cao duc)) va danh vai va thiet*.