Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
toc sach » hoc sach, doc sach, thuoc sach
cham hoc » cham soc, chat hoc, cham hoi
lang van » dang van, tang van, hoang van
hoc van » hoc dan, hoc va, hoc vat
va cham » va chat, va tham
hieu va » lieu va, hieu qua
mang xa » lang xa, mang may, dang xay
luu tre » luu tru, cuu tre, luy tre
vi luu » vi lua

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y ((mang xa) OR (lang van)) hoi. hieu va cham hoc van hanh vi luu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y ((mang xa) or (lang van)) hoi. hieu va cham hoc van hanh vi luu tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y ((mang xa) or (lang van)) hoi. hieu va cham hoc van hanh vi luu tre*.