Perhaps you should try some spelling variations:
doanh ban » doanh bat, doanh van, doanh nhan
cham thuc » nham thuc, pham thuc, tham thuc
ty trang » ta trang, te trang, tu trang
trang xa » trang va, trang ha, trong xa
danh vai » danh sai, danh va, doanh van
co sach » bo sach, cuon sach, hoc sach
thuc va » thuc vat, thuc dan, thuc day
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
hieu ve » hieu van
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach ty trang xa hoi. ((hieu ve) OR (hieu va)) cham thuc va ((danh vai) or (doanh ban)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ty trang xa hoi. ((hieu ve) OR (hieu va)) cham thuc va ((danh vai) OR (doanh ban)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ty trang xa hoi. ((hieu ve) OR (hieu va)) cham thuc va ((danh vai) or (doanh ban)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: co sach ty trang xa hoi. ((hieu ve) OR (hieu va)) cham thuc va ((danh vai) or (doanh ban)) cuu tre*.