Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
doanh qua » doanh quan, doanh cua, danh qua
va doanh » van doanh, vay doanh, va danh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cac dac » cac dan, cac dai, cac bac
qua cua » quan cua, quang cua, qua quan
dac va » duc va, day va, dat va
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: ((tu sach) or (thuat sach)) ky ((nang x) or (nang cao)) hoi. hieu va cac dac va doanh qua cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuat sach)) ky ((nang x) OR (nang cao)) hoi. hieu va cac dac va doanh qua cua te.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat sach)) ky ((nang x) or (nang cao)) hoi. hieu va cac dac va doanh qua cua te*.