Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va doanh » van doanh, vay doanh, hoa doanh
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va danh » va dinh, va dan, va hanh
cua cua » cua chua, ca cua, qua cua
cua te » cua 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 ((nang x) or (nang cao)) hoi. hieu va cac duc ((va doanh) OR (va danh)) cua cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang x) OR (nang cao)) hoi. hieu va cac duc ((va doanh) OR (va danh)) cua cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang x) or (nang cao)) hoi. hieu va cac duc ((va doanh) OR (va danh)) cua cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang x) or (nang cao)) hoi. hieu va cac duc ((va doanh) OR (va danh)) cua cua te*.