Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
cac loai » cac bai, cac giai, cac dai
danh vai » danh sai, danh va, doanh van
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
cac lao » ca lao, cac giao, cac lang
nang xa » nang x, lang xa, nang ma
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cuu tre, cua triet

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 sach)) ky nang xa hoi. hieu vien ((cac lao) OR (cac loai)) va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu sach)) ky nang xa hoi. hieu vien ((cac lao) OR (cac loai)) va danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (vu sach)) ky nang xa hoi. hieu vien ((cac lao) OR (cac loai)) va danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu sach)) ky nang xa hoi. hieu vien ((cac lao) OR (cac loai)) va danh vai cua tre*.