Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, nang ma
qua cam » qua cham, qua cac, qua ca
cam luc » cam xuc, cau luc
v nang » va nang, vu nang, van nang
luc va » duc va, tuc va, loc va
va dan » ca dan, va dao, va dau
dan di » danh di, dan da, dan de
di cau » da cau, diem cau

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 (doc sach)) v nang xa hoi. hieu qua cam luc va dan di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) v nang xa hoi. hieu qua cam luc va dan di cau tren*.