Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
phan dau » phan tu, hang dau
vu khach » vu khanh, vu khac, vay khach
va doanh » van doanh, vay doanh, va danh
su sach » so sach, vu sach
van cua » vang cua, ban cua, dan cua
truc va » thuc va, thuc vat, trung va
van dau » van dao
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
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: ((su sach) or (vu khach)) ky nang ma hoi. hieu ((van dau) OR (phan dau)) truc va doanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu khach)) ky nang ma hoi. hieu ((van dau) OR (phan dau)) truc va doanh van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu khach)) ky nang ma hoi. hieu ((van dau) OR (phan dau)) truc va doanh van cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu khach)) ky nang ma hoi. hieu ((van dau) OR (phan dau)) truc va doanh van cua tre*.