Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thu sac » thu sach, thu san, thu xac
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va hanh » va thanh, va danh, ban hanh
ca tren » cau tren, cu tren, la tren
sac ky » cac ky, sai ky
cac bo » bac bo, cac co
hai ca » hai cua, hai ba, bai ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sac ky nang xa hoi. hieu va ((cac hop) or (cac bo)) ((va hanh) OR (van hanh)) hai ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sac ky nang xa hoi. hieu va ((cac hop) OR (cac bo)) ((va hanh) OR (van hanh)) hai ca tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sac ky nang xa hoi. hieu va ((cac hop) or (cac bo)) ((va hanh) OR (van hanh)) hai ca tren".
• Adding a wildcard symbol may retrieve word variants: thu sac ky nang xa hoi. hieu va ((cac hop) or (cac bo)) ((va hanh) OR (van hanh)) hai ca tren*.