Perhaps you should try some spelling variations:
vien dai » hien dai
vien cac » vien bach, vien da, gian cac
cham hoc » cham soc, chat hoc, cham hoi
hieu va » lieu va, hieu qua
va cham » va chat, va tham
nang xa » nang x, lang xa, nang ma
sach v » sach va, sach y, sach vay
va dan » ca dan, va dao, va dau
sach 2 » sach y

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) or (sach 2)) nang xa hoi. hieu va cham hoc va dan ((vien cac) OR (vien dai)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach v) OR (sach 2)) nang xa hoi. hieu va cham hoc va dan ((vien cac) OR (vien dai)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach v) or (sach 2)) nang xa hoi. hieu va cham hoc va dan ((vien cac) OR (vien dai)) te".
• Adding a wildcard symbol may retrieve word variants: te ((sach v) or (sach 2)) nang xa hoi. hieu va cham hoc va dan ((vien cac) OR (vien dai)) te*.