Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cau treo » cau theo, cau tren, cau triet
doc sach » toc sach, nuoc sach, dac sac
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, van nang
va dan » ca dan, va dao, va dau
dan di » danh di, dan da, dan de
va cao » va cac, va co, va dao

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

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