Perhaps you should try some spelling variations:
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
cuc tre » duc tre, cua tre, cuu tre
su tai » su thi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su tai) or (tu tai)) ky dang xa hoi. hieu ve pham duc ((van hanh) OR (ban hanh)) tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su tai) OR (tu tai)) ky dang xa hoi. hieu ve pham duc ((van hanh) OR (ban hanh)) tai cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su tai) or (tu tai)) ky dang xa hoi. hieu ve pham duc ((van hanh) OR (ban hanh)) tai cuc tre".
• Adding a wildcard symbol may retrieve word variants: ((su tai) or (tu tai)) ky dang xa hoi. hieu ve pham duc ((van hanh) OR (ban hanh)) tai cuc tre*.