Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cac khoi » cac thoi, cac khoan, cach thoi
danh sai » dung sai, danh bat, danh dau
danh vai » danh va, doanh van, dang van
cau tren » cu tren, dau tren, ca tren
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
cau luc » cau truc, cau phuc
lai hoi » dai hoi, lai hoa, lai roi
luc va » duc va, tuc va, loc va
ve cau » ke cau, va cau, ve cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang ((lai hoi) or (cac khoi)). hieu ve cau luc va ((danh vai) OR (danh sai)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((lai hoi) OR (cac khoi)). hieu ve cau luc va ((danh vai) OR (danh sai)) cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((lai hoi) or (cac khoi)). hieu ve cau luc va ((danh vai) OR (danh sai)) cau tren*".