Perhaps you should try some spelling variations:
van doanh » toan doanh, van dong, van thanh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve choi » ve thoi, ve cho, ve khoi
choi xu » choi tu, chi xu, choi au
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
xu van » tu van, vu van, su van

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 ty ((nang ma) or (nang x)) hoi. hieu ve choi xu van doanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang ma) OR (nang x)) hoi. hieu ve choi xu van doanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang ma) or (nang x)) hoi. hieu ve choi xu van doanh tai cua tre*.