Perhaps you should try some spelling variations:
dieu cua » dieu tra
toc sach » hoc sach, doc sach, thuoc sach
dien cuc » dien tu, vien cac, dien hoc
va danh » va dinh, va dan, va hanh
va cham » va chat, va tham
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
soc va » hoc va, loc va, doc va
v nang » va nang, vu nang, van nang

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) or (toc sach)) v nang xa hoi. hieu va cham soc va danh ((dien cuc) OR (dieu cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) v nang xa hoi. hieu va cham soc va danh ((dien cuc) OR (dieu cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) v nang xa hoi. hieu va cham soc va danh ((dien cuc) OR (dieu cua)) te".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) v nang xa hoi. hieu va cham soc va danh ((dien cuc) OR (dieu cua)) te*.