Perhaps you should try some spelling variations:
danh vai » danh sai, danh va, doanh van
su sach » so sach
va danh » va dinh, va dan, va hanh
cao duc » dao duc, giao duc, tao duoc
cao suc » cao su
hieu ve » hieu va, hieu van
tang xa » trang xa, tang ma, lang xa
le tang » le quang, le trung, le thanh
vu sach » vu bach, vu khach
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) OR (vu 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) OR (vu sach)) le tang xa hoi. hieu ve ((cao suc) OR (cao duc)) va danh vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (vu 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) OR (vu sach)) le tang xa hoi. hieu ve ((cao suc) or (cao duc)) va danh vai va thiet*.