Perhaps you should try some spelling variations:
tang hanh » tang thanh, dang hanh, nang hanh
tan hanh » tan thanh, toan hanh, tran hanh
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
dang xa » dang xay, lang xa, dang ha
sac ky » cac ky
ve cam » ve cham, ve cac, va cam

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

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