Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
bac dai » bach mai
va hanh » van hanh, va thanh, va danh
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
va bac » van bac, va cac, va bai
dai va » mai 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 ((y nang) OR (v nang)) ((ma hoa) or (mai hoi)). lieu va bac dai va hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (v nang)) ((ma hoa) OR (mai hoi)). lieu va bac dai va hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) OR (v nang)) ((ma hoa) or (mai hoi)). lieu va bac dai va hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) OR (v nang)) ((ma hoa) or (mai hoi)). lieu va bac dai va hanh vi cua vat*.