Perhaps you should try some spelling variations:
sach ty » sach y, sach tu, sach thu
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
dai hoi » dai hoc, dai moi
dai hai » dai han, dai tai, dai thao
ty nang » ky nang, ty xang, ty hang
va bao » va bai
xuc va » duc va, tuc va, luc va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty nang ((dai hoi) OR (dai hai)). hieu ((va cac) or (va bao)) xuc va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((dai hoi) OR (dai hai)). hieu ((va cac) OR (va bao)) xuc va hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((dai hoi) OR (dai hai)). hieu ((va cac) or (va bao)) xuc va hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((dai hoi) OR (dai hai)). hieu ((va cac) or (va bao)) xuc va hanh vi cua vat*.