Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
van chat » cao chat
hang dau » hang va, hang tai
dau cua » dai cua, day cua, cau cua
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
loc va » hoc va, luc va
doc va » duoc va, hoc va, duc va
y nang » ky nang, ly nang, v nang
goc va » hoc va, uoc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang xa hoi. hieu van chat ((((goc va) OR (loc va))) or (doc va)) hang dau cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hieu van chat ((((goc va) OR (loc va))) OR (doc va)) hang dau cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. hieu van chat ((((goc va) OR (loc va))) or (doc va)) hang dau cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. hieu van chat ((((goc va) OR (loc va))) or (doc va)) hang dau cua viet*.