Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van chat » cao chat
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
cau cua » ca cua, cu cua, chat cua
y nang » ky nang, ly nang, v nang
soc va » hoc va, loc va, goc va
doc va » duoc va, hoc va, duc 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 ((soc va) or (doc va)) danh ((cau cua) OR (cau qua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hieu van chat ((soc va) OR (doc va)) danh ((cau cua) OR (cau qua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. hieu van chat ((soc va) or (doc va)) danh ((cau cua) OR (cau qua)) viet".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. hieu van chat ((soc va) or (doc va)) danh ((cau cua) OR (cau qua)) viet*.