Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
dan doanh » van doanh, san doanh, ban doanh
thu sach » tu sach, thuat sach, thuoc sach
nang noi » nang doc
thuc dan » thuc hanh, hoc dan, thuc vat
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
nang co » nang cao, nang doc, nang hoc
hieu va » lieu va, hieu qua
van su » dan su
va am » va lam, va cam

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang co) OR (nang noi)) hoi. hieu va am thuc dan doanh van su triet~.
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang co) or (nang noi)) hoi. hieu va am thuc dan doanh van su triet*.