Perhaps you should try some spelling variations:
van doanh » toan doanh, van dong, van thanh
hieu hien » bieu hien, dieu hien, chieu chien
sach kem » hanh kem
doanh va » doan va, doanh tai, doanh cua
hien cac » thien cac, vien cac, hieu cac
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, nang ma, mang xa
sac ky » cac ky, sai ky
cac le » cach le, cac he, mac le
va cua » va chua, via cua, ca cua

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 kem) or (sac ky)) ((nang xa) OR (lang xa)) hoi. hieu hien cac le van doanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach kem) OR (sac ky)) ((nang xa) OR (lang xa)) hoi. hieu hien cac le van doanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach kem) or (sac ky)) ((nang xa) OR (lang xa)) hoi. hieu hien cac le van doanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach kem) or (sac ky)) ((nang xa) OR (lang xa)) hoi. hieu hien cac le van doanh va cua tre*.