Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hieu vien » hieu viec, thieu nien, hieu tieng
tu sach » thu sach, te sach, tu cach
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
cac dac » cac dan, cac dai, cac bac
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
y nang » ky nang, ly nang, v nang
dac va » duc va, day va, dat va
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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) or (su sach)) y nang x hoi. ((hieu vien) or (hieu hien)) cac dac va danh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) y nang x hoi. ((hieu vien) OR (hieu hien)) cac dac va danh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) y nang x hoi. ((hieu vien) or (hieu hien)) cac dac va danh vi cua tre*.