Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
cham xuc » cam xuc, chat xuc, cham soc
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
cua viet » ca viet, hoa viet, cua vat
cao hoc » co hoc, cho hoc, chat hoc
va hanh » va thanh, va danh, ban hanh
hai cua » thai cua, dai cua, hoi cua
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach v nang ((cau hoi) or (cao hoc)). hieu van cham xuc ((va hanh) OR (van hanh)) hai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v nang ((cau hoi) OR (cao hoc)). hieu van cham xuc ((va hanh) OR (van hanh)) hai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v nang ((cau hoi) or (cao hoc)). hieu van cham xuc ((va hanh) OR (van hanh)) hai cua viet".
• Adding a wildcard symbol may retrieve word variants: toc sach v nang ((cau hoi) or (cao hoc)). hieu van cham xuc ((va hanh) OR (van hanh)) hai cua viet*.