Perhaps you should try some spelling variations:
hieu vien » hieu viec, thieu nien, hieu tieng
hieu hien » bieu hien, dieu hien, chieu chien
vai cuu » vai cua
va dinh » van dinh, va kinh, va tinh
cuu tre » cua tre, cau tren, cau treo
nang xa » nang x, lang xa, nang ma
cac lo » cac lop, cac co, cac bo
sac ky » cac ky, sai ky
tu sac » tu sach, tu cac, tu san

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky nang xa hoi. ((hieu vien) OR (hieu hien)) cac lo ((xuan dinh) or (va dinh)) vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang xa hoi. ((hieu vien) OR (hieu hien)) cac lo ((xuan dinh) OR (va dinh)) vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang xa hoi. ((hieu vien) OR (hieu hien)) cac lo ((xuan dinh) or (va dinh)) vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang xa hoi. ((hieu vien) OR (hieu hien)) cac lo ((xuan dinh) or (va dinh)) vai cuu tre*.