Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
dang xay » dang van, van xay
van chat » cao chat
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
su sach » so sach, vu sach
soc va » hoc va, doc va, goc va
loc va » hoc va, luc va
dao va » dao van, tao va, do va

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 ty ((nang xa) or (dang xay)) hoi. hieu van chat ((soc va) or (loc va)) lanh dao va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang xa) OR (dang xay)) hoi. hieu van chat ((soc va) OR (loc va)) lanh dao va triet.
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang xa) or (dang xay)) hoi. hieu van chat ((soc va) or (loc va)) lanh dao va triet*.