Perhaps you should try some spelling variations:
can thiet » dan thiet, cac thiet, cad thiet
van thiet » va thiet, dan thiet, van thien
van hanh » van thanh, ban hanh, van anh
chat xuc » chat huu, cam xuc, chao xu
ve chat » va chat, van chat
xuc van » duc van, luc van, vuc van
su sach » so sach
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
vu sach » vu bach, vu khach
hieu ve » hieu va, hieu van

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)) ky tang xa hoi. hieu ve chat xuc van hanh vi ((van thiet) OR (can thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ky tang xa hoi. hieu ve chat xuc van hanh vi ((van thiet) OR (can thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) ky tang xa hoi. hieu ve chat xuc van hanh vi ((van thiet) OR (can thiet))".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ky tang xa hoi. hieu ve chat xuc van hanh vi ((van thiet) OR (can thiet))*.