Perhaps you should try some spelling variations:
doanh cuan » doanh luan, doanh quan, doanh quang
doanh cua » doanh luan
tham thuc » nham thuc, pham thuc, tam thuc
cua tre » cuu tre, cua triet, dua tren
tu sach » thu sach, su sach, te sach
sach ta » sach tai, sach xa, sach ha
thuc va » thuc vat, thuc dan, thuc day
va tham » van tham, va cham, va thanh
hieu va » lieu va, hieu qua
ta hang » va hang, ty hang, te hang
va hoi » xa hoi, va hoc, va hoa
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 ta hang va hoi. hieu va tham thuc va ((doanh cuan) or (doanh cua)) ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ta hang va hoi. hieu va tham thuc va ((doanh cuan) OR (doanh cua)) ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: tu sach ta hang va hoi. hieu va tham thuc va ((doanh cuan) or (doanh cua)) ((cua tre) or (cua te))*.