Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thu bang » thu ban, thu hang, chu bang
cau treo » cau theo, cau tren, cau triet
thu nang » thi nang, thu hang, tho nang
hieu va » lieu va, hieu qua
va hang » van hang, va nang, va lang
hang vi » hang va, hanh vi, hang di
cuu tre » cua tre, cau tren
cam tu » cam thu, nam tu, dam tu
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 ((thu nang) OR (thu bang)) xa hoi. hieu va cam tu va hang vi ((cuu tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((thu nang) OR (thu bang)) xa hoi. hieu va cam tu va hang vi ((cuu tre) OR (cau treo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((thu nang) OR (thu bang)) xa hoi. hieu va cam tu va hang vi ((cuu tre) or (cau treo))".
• Adding a wildcard symbol may retrieve word variants: toc sach ((thu nang) OR (thu bang)) xa hoi. hieu va cam tu va hang vi ((cuu tre) or (cau treo))*.