Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
ban thanh » ban hanh, ban hang
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
cay lua » vay luan
vai cau » va cau, van cau, vai cac
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, mai doi
lai hoi » dai hoi, lai hoa, lai roi
y nang » ky nang, ly nang, v nang

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 ((mai hoi) OR (lai hoi)). hieu van ((cay lua) or (chay dua)) ban thanh vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((mai hoi) OR (lai hoi)). hieu van ((cay lua) OR (chay dua)) ban thanh vai cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((mai hoi) OR (lai hoi)). hieu van ((cay lua) or (chay dua)) ban thanh vai cau tren".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((mai hoi) OR (lai hoi)). hieu van ((cay lua) or (chay dua)) ban thanh vai cau tren*.