Perhaps you should try some spelling variations:
hieu tieng » viet tieng, dien tieng, tiep tieng
hieu hien » bieu hien, dieu hien, chieu chien
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
cac tac » cac toc, cac bac, cac dac
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty nang xa hoi. ((hieu tieng) or (hieu hien)) ((cac tac) or (cac nuoc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. ((hieu tieng) OR (hieu hien)) ((cac tac) OR (cac nuoc)) va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. ((hieu tieng) or (hieu hien)) ((cac tac) or (cac nuoc)) va hanh vi cua tre*.