Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tham xuc » tham nuoc, tham thuc, pham duc
sach ty » sach y, sach tu, sach thu
va hanh » van hanh, va thanh, va danh
ty nang » ky nang, ty xang, ty hang
vai cau » va cau, van cau, lai chau
vai cac » va cac, tai cac, voi cac
tu sach » thu sach, su sach, te sach
xuc va » duc va, tuc va, luc va
x hoi » xa hoi, o hoi, 5 hoi

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 ty nang ((x hoi) OR (x ho)). hieu van tham xuc va hanh ((vai cau) OR (vai cac)) tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((x hoi) OR (x ho)). hieu van tham xuc va hanh ((vai cau) or (vai cac)) tren~".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((x hoi) OR (x ho)). hieu van tham xuc va hanh ((vai cau) or (vai cac)) tren*.