Perhaps you should try some spelling variations:
nhieu vien » nhieu viec, nhiet dien, thieu nien
trinh de » trinh den, trinh do, trinh he
va trinh » van trinh, va tinh, lap trinh
vien dao » vien dai, vien da, vien cao
tu sach » thu sach, te sach, tu cach
dao duc » giao duc, tao duoc
cua tre » cua te, cuu tre, cua triet
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
su sach » so sach, vu sach
de cua » le cua, te cua, dieu cua

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