Perhaps you should try some spelling variations:
quoc van » quoc va, quoc ban, quoc lan
cuoc van » cuoi van, luoc van, cuu van
tu sach » thu sach, su sach, te sach
su kham » su pham, vu kham, so kham
hanh de » hanh ve, hanh kem
hieu su » hieu sau, tieu su, hieu so
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
de cua » le cua, te cua, dieu 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: tu sach ky ((nang xa) OR (nang ma)) hoi. hieu su kham ((cuoc van) OR (quoc van)) hanh de cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) or (nang ma)) hoi. hieu su kham ((cuoc van) OR (quoc van)) hanh de cua te~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang ma)) hoi. hieu su kham ((cuoc van) OR (quoc van)) hanh de cua te*.