Perhaps you should try some spelling variations:
van thiet » va thiet, dan thiet, can thiet
chat huu » pham huu
van hanh » van thanh, ban hanh, van anh
su sach » so sach
vu sach » vu bach, vu khach
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
huu van » cuu van, huu han, luu 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 huu van hanh vi van 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 huu van hanh vi van thiet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ky tang xa hoi. hieu ve chat huu van hanh vi van thiet*.