Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
doc sach » toc sach, nuoc sach, dac sac
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
cuu tre » cua tre, cau tren, cau treo
v nang » va nang, vu nang, van nang
nang o » nang co, nang ho, nang ro
va cam » va cham, va cac, va cao
luc va » duc va, tuc va, loc va
di cuu » di cau, di cua, dinh cuu
o hoi » co hoi, o hoc, o hai

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 o hoi. hieu va cam luc va danh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (doc sach)) v nang o hoi. hieu va cam luc va danh di cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (doc sach)) v nang o hoi. hieu va cam luc va danh di cuu tre*.