Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
toc sach » hoc sach, doc sach, thuoc sach
van bac » van bao, van hac, dan bac
truc va » thuc vat, trung va
thuc va » thuc vat, thuc dan, thuc day
nang ma » tang ma, sang ma, nang cao
van cua » vang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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: toc sach y nang ma hoi. hieu ((van bac) or (van ban)) ((truc va) OR (thuc va)) doanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ma hoi. hieu ((van bac) OR (van ban)) ((truc va) OR (thuc va)) doanh van cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang ma hoi. hieu ((van bac) or (van ban)) ((truc va) OR (thuc va)) doanh van cua tre*".