Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
va thanh » gia thanh, ban thanh, va tinh
bach ky » bac ky
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
su viet » so viet
cam tu » cam thu, nam tu, dam tu
ki su » ky su

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu bach ky nang xa hoi. ((hieu van) OR (hieu va)) cam tu ((va thanh) or (va danh)) ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu bach ky nang xa hoi. ((hieu van) OR (hieu va)) cam tu ((va thanh) OR (va danh)) ki su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu bach ky nang xa hoi. ((hieu van) OR (hieu va)) cam tu ((va thanh) or (va danh)) ki su viet".
• Adding a wildcard symbol may retrieve word variants: vu bach ky nang xa hoi. ((hieu van) OR (hieu va)) cam tu ((va thanh) or (va danh)) ki su viet*.