Perhaps you should try some spelling variations:
thieu nien » thien nhien
thu sach » tu sach, thuat sach, thuoc sach
trinh ve » trinh he, trinh va, trinh vi
va trinh » van trinh, va tinh, lap trinh
dai dua » dai cua, dai sua, dai luan
dai duc » dao duc, mai duc, dai dac
cao hoi » cau hoi, co hoi, cao hoc
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
ve cua » le cua, de cua, te cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (su sach)) ky nang cao hoi. thieu nien ((dai duc) OR (dai dua)) va trinh ve cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (su sach)) ky nang cao hoi. thieu nien ((dai duc) OR (dai dua)) va trinh ve cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (su sach)) ky nang cao hoi. thieu nien ((dai duc) OR (dai dua)) va trinh ve cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (su sach)) ky nang cao hoi. thieu nien ((dai duc) OR (dai dua)) va trinh ve cua tre*.