Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
v lang » va lang, o lang, _ lang
cua tu » cua tuc, cua su, cua cu

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

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