Perhaps you should try some spelling variations:
cham luc » cham soc, nhan luc, cham cuu
phan tai » pham tai, nhan tai, phan thi
su sach » so sach, vu sach
nang xa » lang xa, nang ma, mang xa
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
va phan » van phan, va phat, va phap
luc va » duc va, tuc va, loc va
tai va » thai va, mai va, tri va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((nang xa) or (nang x)) hoi. hieu ve cham luc va phan tai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang x)) hoi. hieu ve cham luc va phan tai va thiet.
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (nang x)) hoi. hieu ve cham luc va phan tai va thiet*.