Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
doc sach » hoc sach, toc sach, nuoc sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, van nang
luc va » duc va, tuc va, loc va
di cua » dai cua, doi cua, de cua

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

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