Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
va doanh » van doanh, vay doanh, va danh
ky dang » ky nang
ky danh » ky anh
hieu va » lieu va
cac mai » cac bai, cac dai, cac mau
cuc tre » duc tre, cua tre, cuu tre
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 ((ky dang) or (ky danh)) ma hoi. ((hieu va) or (hieu qua)) cac mai va doanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((ky dang) OR (ky danh)) ma hoi. ((hieu va) OR (hieu qua)) cac mai va doanh tai cuc tre.
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((ky dang) or (ky danh)) ma hoi. ((hieu va) or (hieu qua)) cac mai va doanh tai cuc tre*.