Perhaps you should try some spelling variations:
pham tai » pham thi, pham van
phan tai » nhan tai, phan thi, han tai
cham luc » cham soc, nhan luc, cham cuu
su sach » so sach, vu sach
ve cham » va cham, ve chat, vu cham
nang xa » lang xa, nang ma, mang xa
hieu ve » hieu va, hieu van
luc va » duc va, tuc va, loc 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) OR (pham 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) OR (pham tai)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) or (nang x)) hoi. hieu ve cham luc va ((phan tai) OR (pham 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) OR (pham tai)) va thiet*.