Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh ban
viec cac » vien cac, viec lam, viec va
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
van cu » van cau, van chu, van cua
cu tre » cu tren, cua tre, cuu tre

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 ky nang xa hoi. hieu ((viec cac) OR (viec cua)) ((vo van) or (le van)) doanh van cu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu ((viec cac) OR (viec cua)) ((vo van) OR (le van)) doanh van cu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu ((viec cac) OR (viec cua)) ((vo van) or (le van)) doanh van cu tre*".