Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hieu va » hieu qua
cam luc » cam xuc, cau luc
va dinh » van dinh, va kinh, va tinh
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
luc va » duc va, tuc va, loc va
di cua » doi cua, de cua, do cua
x hoi » xa hoi, o hoi, x ho

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

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