Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dinh cuu » dinh chi
doc sach » toc sach, nuoc sach, dac sac
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
nang ro » nang co, nang ho, nang ra
ro hoc » co hoc, mo hoc, o hoc
v nang » va nang, vu nang, van nang
va dan » ca dan, va dau, va dap
va dao » ca dao
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: ((hoc sach) or (doc sach)) v nang ro hoc. hieu va cam luc ((va dan) OR (va dao)) dinh cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (doc sach)) v nang ro hoc. hieu va cam luc ((va dan) OR (va dao)) dinh cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc sach) or (doc sach)) v nang ro hoc. hieu va cam luc ((va dan) OR (va dao)) dinh cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (doc sach)) v nang ro hoc. hieu va cam luc ((va dan) OR (va dao)) dinh cuu tre*.