Perhaps you should try some spelling variations:
nhieu vien » nhieu viec, nhiet dien, thieu nien
trinh den » trinh dien, trinh dan, trinh dung
vien dai » hien dai
trinh de » trinh do, trinh he, trinh di
dai duc » dao duc, dai dua, mai duc
tu sach » thu sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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)) ky nang ma hoi. nhieu vien dai duc va ((trinh de) OR (trinh den)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang ma hoi. nhieu vien dai duc va ((trinh de) OR (trinh den)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky nang ma hoi. nhieu vien dai duc va ((trinh de) OR (trinh den)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang ma hoi. nhieu vien dai duc va ((trinh de) OR (trinh den)) cua tre*.