Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
dieu cua » dieu tra
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
qua dau » qua da, qua bau, qua dan
dau luc » cau luc, dau luan, dau nuoc
luc van » luoc van, luu van, duc van
vi cua » vai cua, di 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 _ lang xa hoi. hieu qua dau luc van hanh ((vi cua) or (dieu cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach _ lang xa hoi. hieu qua dau luc van hanh ((vi cua) OR (dieu cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach _ lang xa hoi. hieu qua dau luc van hanh ((vi cua) or (dieu cua)) tre*.