Perhaps you should try some spelling variations:
van doanh » toan doanh, van dong, van thanh
tu sach » thu sach, su sach, te sach
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
lang xa » lang ha, dang xay, lang van
qua cam » qua cham, qua cac, qua ca
cam luc » cam xuc, cau luc
luc van » luoc van, luu van, duc van
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet

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 y ((((nang ma) OR (sang ma))) or (lang xa)) hoi. hieu qua cam luc van doanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((((nang ma) OR (sang ma))) OR (lang xa)) hoi. hieu qua cam luc van doanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((((nang ma) OR (sang ma))) or (lang xa)) hoi. hieu qua cam luc van doanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((((nang ma) OR (sang ma))) or (lang xa)) hoi. hieu qua cam luc van doanh tai cua tre*.