Perhaps you should try some spelling variations:
kham cuu » cham cuu, khao cuu, kham chua
va kham » va cham, va khao, va tham
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
sach v » sach va, sach 2, sach vay
ve dan » ke dan, le dan, he dan
va dan » ca dan, va dao, va dau
va cua » va chua, via cua, ca cua
cua te » cua tu

You may be able to get more results by adjusting your search query.

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