Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
hang vai » hang va, hang tai, hang hai
thu sach » thuat sach, thuoc sach, thu hoach
va hang » van hang, va nang, va lang
cac toc » cac toi, cac nuoc, cac thoi
cac tuc » cac tu, cac tac, cac nuoc
tu sach » su sach, te sach, tu cach
hieu ve » hieu va, hieu van
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
vai va » mai va, dai va, hai va

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: ((tu sach) OR (thu sach)) ky tang xa hoi. hieu ve ((cac tuc) OR (cac toc)) va hang vai va trien~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky tang xa hoi. hieu ve ((cac tuc) OR (cac toc)) va hang vai va trien~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky tang xa hoi. hieu ve ((cac tuc) OR (cac toc)) va hang vai va trien*.