Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
luc ngan » luc nganh, luc nhan, luat ngan
dua tren » dung tren
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
van cam » van nam, van lam, van cau
cam luc » cam xuc, cau luc
hang vi » hang va, hanh vi, hang di
vi dua » vi du, vi dum, vi lua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu ((nang xa) OR (nang x)) hoi. hieu van cam luc ngan hang vi dua tren~.
• Adding a wildcard symbol may retrieve word variants: tu sach thu ((nang xa) or (nang x)) hoi. hieu van cam luc ngan hang vi dua tren*.