Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
te sach » toc sach
va hanh » van hanh, va danh, ban hanh
va cham » va chat, va tham
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
sach v » sach va, sach y, sach 2
tu te » tu tu, tu le

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