Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
van hanh » van thanh, ban hanh, van anh
hoc sach » hoc sinh, hoc cac, hoc anh
dau thuc » dan thuc, dai thuc, dam thuc
va hanh » va thanh, va danh, ban hanh
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
va dau » va dao
v nang » va nang, vu nang, van nang
vi cua » vai cua, di cua
cua te » cua tu

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