Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
lang van » dang van, tang van, hoang van
cau treo » cau theo, cau tren, cau triet
lang xa » lang ha, dang xay
cac dac » cac dan, cac dai, cac bac
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
sach v » sach va, sach y, sach 2
dac va » duc va, day va, dat va

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach v ((lang xa) or (lang van)) hoi. hieu va cac dac va hanh di ((cua tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach v ((lang xa) OR (lang van)) hoi. hieu va cac dac va hanh di ((cua tre) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: doc sach v ((lang xa) or (lang van)) hoi. hieu va cac dac va hanh di ((cua tre) or (cau treo))*.