Perhaps you should try some spelling variations:
hieu vien » hieu viec, thieu nien, hieu tieng
hieu hien » bieu hien, dieu hien, chieu chien
lanh thai » lanh hai, anh thai, lang thai
thai cua » than cua, tai cuc, tri cua
tu sach » thu sach, su sach, te sach
va lanh » va lang, va danh, va hanh
cua tre » cua te, cuu tre, cua triet
da tao » dao tao, de tao, da bao
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 (vu bach)) ky nang x hoi. ((hieu vien) OR (hieu hien)) da tao va lanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu bach)) ky nang x hoi. ((hieu vien) OR (hieu hien)) da tao va lanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (vu bach)) ky nang x hoi. ((hieu vien) OR (hieu hien)) da tao va lanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu bach)) ky nang x hoi. ((hieu vien) OR (hieu hien)) da tao va lanh thai cua tre*.