Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
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 luu » dan luu, dau luan, dau luot
luu van » cuu van, luan van, luu hanh
y lang » o lang, _ lang, tay lang
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 y lang xa hoi. hieu qua dau luu van hanh ((vi cua) or (de cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y lang xa hoi. hieu qua dau luu van hanh ((vi cua) OR (de cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y lang xa hoi. hieu qua dau luu van hanh ((vi cua) or (de cua)) tre*.