Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
cau treo » cau theo, cau tren, cau triet
doc sach » hoc sach, nuoc sach, dac sac
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
va dan » va dao, va dau, va dap
ca dan » cac dan, ca dao
du cau » cu cau, da cau, di cau
va cam » va cham, va cac, va cao

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