Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dien duc » dien cuc, dien luc, tien duc
va dinh » van dinh, va kinh, va tinh
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
duc tre » duoc tren, duc tien
vu nang » vuc nang, va nang, vu dang
nang o » nang co, nang ho, nang ro
va dan » ca dan, va dao, va dau
va cam » va cham, va cac, va cao
o hoc » co hoc, mo hoc, so hoc

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 (dac sac)) vu nang o hoc. hieu va cam luc ((va dan) or (va dinh)) dien duc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (dac sac)) vu nang o hoc. hieu va cam luc ((va dan) OR (va dinh)) dien duc tre.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (dac sac)) vu nang o hoc. hieu va cam luc ((va dan) or (va dinh)) dien duc tre*.