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
cao suc » cao su, cao duc
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
sach ky » sac ky, sach y, sach ty
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, ky tang

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