Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
nang xa » lang xa, nang ma, mang xa
hieu va » lieu va, hieu qua
cac lop » cac hop, cac loai
va hanh » va thanh, va danh, ban hanh
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
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 sac ky ((nang xa) or (nang x)) hoi. hieu va cac lop ((va hanh) OR (van hanh)) dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((nang xa) OR (nang x)) hoi. hieu va cac lop ((va hanh) OR (van hanh)) dai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((nang xa) or (nang x)) hoi. hieu va cac lop ((va hanh) OR (van hanh)) dai cua te*".