Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
lang van » dang van, tang van, hoang van
ve triet » va trien, su triet
doc sach » hoc sach, nuoc sach, dac sac
lang xa » lang ha, dang xay
nam xua » nam cua, nam mua, nam qua
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
xua va » xuat va, vua va, sua va
ve ve » de ve, va ve, ke ve

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) OR (doc sach)) ky ((lang xa) or (lang van)) hoi. hieu van nam xua va hanh ve ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky ((lang xa) OR (lang van)) hoi. hieu van nam xua va hanh ve ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ky ((lang xa) or (lang van)) hoi. hieu van nam xua va hanh ve ve triet".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) ky ((lang xa) or (lang van)) hoi. hieu van nam xua va hanh ve ve triet*.