Perhaps you should try some spelling variations:
sach dao » lanh dao
dieu tra » dieu tri, kiem tra, dieu cua
sach va » sach xa, sach ha, sach nha
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
soc va » hoc va, loc va, doc va
luc va » duc va, tuc va, loc va
tra te » tra tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach va) OR (sach dao)) nang xa hoi. hieu ve cham ((soc va) or (luc va)) dang dieu tra te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach va) OR (sach dao)) nang xa hoi. hieu ve cham ((soc va) OR (luc va)) dang dieu tra te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach va) OR (sach dao)) nang xa hoi. hieu ve cham ((soc va) or (luc va)) dang dieu tra te".
• Adding a wildcard symbol may retrieve word variants: te ((sach va) OR (sach dao)) nang xa hoi. hieu ve cham ((soc va) or (luc va)) dang dieu tra te*.