Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
danh bai » anh bai, danh bat, dang bai
nam thuc » nam thuoc, am thuc, nam thu
mai khoi » mai khoa, tai khoa, cac khoi
cam tuc » cam xuc, cam tu, dam thuc
va danh » va dinh, va dan, va hanh
cu tren » tu tren, dua tren
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
lai roi » lai hoi, loi roi
ky sang » ky nang, ky dang, ky tang
bai cu » bai cua, bai ca, bai tu

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 sang ((lai roi) or (mai khoi)). hieu ve ((cam tuc) OR (nam thuc)) va danh bai cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky sang ((lai roi) OR (mai khoi)). hieu ve ((cam tuc) OR (nam thuc)) va danh bai cu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky sang ((lai roi) or (mai khoi)). hieu ve ((cam tuc) OR (nam thuc)) va danh bai cu tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ky sang ((lai roi) or (mai khoi)). hieu ve ((cam tuc) OR (nam thuc)) va danh bai cu tren*.