Perhaps you should try some spelling variations:
doanh luan » doanh nhan
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty vang » ty xang, ty van, ly vang
vang xa » lang xa, mang xa, ang xa
dau luu » dan luu, dau luan, dau luot
vi cua » vai cua, di cua
de cua » le cua, te cua, dieu 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 ty vang xa hoi. hieu qua ((dau luu) or (doanh luan)) van hanh ((vi cua) or (de cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty vang xa hoi. hieu qua ((dau luu) OR (doanh luan)) van hanh ((vi cua) OR (de cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ty vang xa hoi. hieu qua ((dau luu) or (doanh luan)) van hanh ((vi cua) or (de cua)) tre*.