Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
hieu van » hieu va, thien van, lieu va
hanh te » hanh tu, hanh ve, hanh de
cuu tac » cuu dac, cuu cac, cuu xac
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
te cua » tue cua, le cua, de cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) OR (sach y)) nang xa hoi. hieu van ((cuu thuc) or (cuu tac)) vat hanh te cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang xa hoi. hieu van ((cuu thuc) OR (cuu tac)) vat hanh te cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sach y)) nang xa hoi. hieu van ((cuu thuc) or (cuu tac)) vat hanh te cua te".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sach y)) nang xa hoi. hieu van ((cuu thuc) or (cuu tac)) vat hanh te cua te*.