Perhaps you should try some spelling variations:
thuoc sach » nuoc sach, thuat sach, thuoc sinh
hoc sach » hoc sinh, hoc cac, hoc anh
va doanh » van doanh, vay doanh, va danh
tai cuu » tai cuc, tai buu, tai cua
cao suc » cao su, cao duc
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
cuu tre » cua tre, cau tren, cau treo
ma hoi » mai hoi, xa hoi, ma hoa

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