Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
sang mai » sang ma, sang tai, lang mai
va doanh » van doanh, vay doanh, va danh
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
cao duc » dao duc, cao suc, tao duoc
cuc tre » cua tre, cuu tre, cuc thue
duc tre » duoc tren, duc tien

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ky sang mai hoi. lieu va ((cao duc) or (giao duc)) va doanh tai ((cuc tre) OR (duc tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky sang mai hoi. lieu va ((cao duc) OR (giao duc)) va doanh tai ((cuc tre) OR (duc tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky sang mai hoi. lieu va ((cao duc) or (giao duc)) va doanh tai ((cuc tre) OR (duc tre))".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky sang mai hoi. lieu va ((cao duc) or (giao duc)) va doanh tai ((cuc tre) OR (duc tre))*.