Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hang hai » hoang hai, hang tai, thanh hai
hai cua » thai cua, dai cua, hoi cua
va hang » van hang, va nang, va lang
va chat » van chat, va phat, cao chat
cua tre » cua te, cuu tre, cua triet
va cham » va tham
ly nang » ky nang, ly hang, ly vang
y nang » ky nang, v nang, may nang
ma hoi » mai hoi, xa hoi, ma hoa
xuc va » duc va, tuc va, luc 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: doc sach ((y nang) OR (ly nang)) ma hoi. lieu ((va cham) OR (va chat)) xuc va hang hai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((y nang) OR (ly nang)) ma hoi. lieu ((va cham) or (va chat)) xuc va hang hai cua tre~".
• Adding a wildcard symbol may retrieve word variants: doc sach ((y nang) OR (ly nang)) ma hoi. lieu ((va cham) or (va chat)) xuc va hang hai cua tre*.