Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cua tre » cuu tre, cua triet, dua tren
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 hoi. hieu va ((dat nuoc) or (hoc nuoc)) van hanh dai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang xa hoi. hieu va ((dat nuoc) OR (hoc nuoc)) van hanh dai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang xa hoi. hieu va ((dat nuoc) or (hoc nuoc)) van hanh dai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang xa hoi. hieu va ((dat nuoc) or (hoc nuoc)) van hanh dai ((cua tre) OR (cua te))*.