Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
ban hang » ngan hang
nhan luc » nang luc
cua nhan » ca nhan, cua ngan, cua nha
hieu cua » hieu qua, dieu cua, bieu cua
su triet » su viet, su tien, ve triet
dang xay » dang van, van xay
sach ky » sac ky, sach y, sach ty
luc ban » duc ban, cuc ban, luc bat
nang xa » nang x, lang xa, nang ma

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky ((nang xa) or (dang xay)) hoi. hieu cua nhan luc ban hang va ((va thiet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang xa) OR (dang xay)) hoi. hieu cua nhan luc ban hang va ((va thiet) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang xa) or (dang xay)) hoi. hieu cua nhan luc ban hang va ((va thiet) or (su triet))*.