Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
van thanh » ban thanh, van tuan
vien cac » vien bach, vien dai, vien da
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
cuc tre » duc tre, cua tre, cuu tre
ma hoi » xa hoi, ma hoa, me hoi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((ma hoi) OR (mai hoi)). hieu vien cac nuoc ((van thanh) OR (va danh)) tai cuc tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ((ma hoi) OR (mai hoi)). hieu vien cac nuoc ((van thanh) or (va danh)) tai cuc tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((ma hoi) OR (mai hoi)). hieu vien cac nuoc ((van thanh) or (va danh)) tai cuc tre*.