Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, hoc sach, cuoc cach
toc sach » hoc sach, thuoc sach, toc san
doc sach » hoc sach, dac sac, bo sach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cam luc » cam xuc, cau luc
va hang » van hang, va nang, va lang
hang di » hang doi, hang vi, hang dien
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, van nang
va cam » va cham, va cac, va cao
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: ((((toc sach) OR (nuoc sach))) or (doc sach)) v nang xa hoi. hieu va cam luc va hang di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((toc sach) OR (nuoc sach))) OR (doc sach)) v nang xa hoi. hieu va cam luc va hang di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((toc sach) OR (nuoc sach))) or (doc sach)) v nang xa hoi. hieu va cam luc va hang di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((((toc sach) OR (nuoc sach))) or (doc sach)) v nang xa hoi. hieu va cam luc va hang di cua tre*.