Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dieu cua » dieu tra
doc sach » toc sach, nuoc sach, dac sac
dan dieu » dang dieu, doan dieu, da dieu
cau luc » cau truc, cau phuc
hieu va » lieu va, hieu qua
vu nang » vuc nang, va nang, vu dang
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
va dan » ca dan, va dao, va dau
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 (doc sach)) vu nang o hoc. hieu va ((cau luc) or (cam xuc)) va dan dieu cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (doc sach)) vu nang o hoc. hieu va ((cau luc) OR (cam xuc)) va dan dieu cua tre.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (doc sach)) vu nang o hoc. hieu va ((cau luc) or (cam xuc)) va dan dieu cua tre*.