Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van chat » cao chat
dieu cua » dieu tra
te sach » toc sach
dien cu » dien cuc, dien cua, dien tu
nang xa » nang x, lang xa, nang ma
bao va » bao ve, tao va, ban va
sach 2 » sach y
2 nang » v nang
bo va » do va, so va, co va

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 2 nang xa hoi. hieu van chat ((bo va) OR (bao va)) dinh ((dieu cua) or (dien cu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach 2 nang xa hoi. hieu van chat ((bo va) OR (bao va)) dinh ((dieu cua) OR (dien cu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach 2 nang xa hoi. hieu van chat ((bo va) OR (bao va)) dinh ((dieu cua) or (dien cu)) tre".
• Adding a wildcard symbol may retrieve word variants: te sach 2 nang xa hoi. hieu van chat ((bo va) OR (bao va)) dinh ((dieu cua) or (dien cu)) tre*.