Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tham luc » than luc, tham nuoc, tham thuc
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
va nang » van nang, da nang, cam nang
cuu tre » cua tre, cau tren, cau treo
v nang » vu nang, van nang, voi nang
va dan » ca dan, va dau, va dap
va dao » ca dao
du cuu » tu cuu

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 ((v nang) OR (va nang)) xa hoi. hieu va tham luc ((va dan) or (va dao)) du cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((v nang) OR (va nang)) xa hoi. hieu va tham luc ((va dan) OR (va dao)) du cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((v nang) OR (va nang)) xa hoi. hieu va tham luc ((va dan) or (va dao)) du cuu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((v nang) OR (va nang)) xa hoi. hieu va tham luc ((va dan) or (va dao)) du cuu tre*.