Perhaps you should try some spelling variations:
dang xay » dang van, van xay
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac hoc » cach hoc, cac hop, bac hoc
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
te van » le van, te va, ve van
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: te van ky ((nang xa) or (dang xay)) hoi. hieu va cac hoc ((va hanh) OR (va danh)) dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te van ky ((nang xa) OR (dang xay)) hoi. hieu va cac hoc ((va hanh) OR (va danh)) dai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te van ky ((nang xa) or (dang xay)) hoi. hieu va cac hoc ((va hanh) OR (va danh)) dai cua te".
• Adding a wildcard symbol may retrieve word variants: te van ky ((nang xa) or (dang xay)) hoi. hieu va cac hoc ((va hanh) OR (va danh)) dai cua te*.