Perhaps you should try some spelling variations:
thieu nien » thien nhien
bach tuoc » sach duoc, sach nuoc
nien bach » vien bach, dien sach, mien bac
van hanh » van thanh, ban hanh, van anh
va danh » va dinh, va dan, va hanh
cua tre » cua te, cuu tre, cua triet
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
de cua » le cua, te cua, dieu cua
su cac » tu cac, su cao, su can

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

• Performing a fuzzy search may retrieve terms with similar spellings: su cac ((ky lang) OR (ky tang)) xa hoi. thieu nien bach tuoc ((van hanh) or (va danh)) de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cac ((ky lang) OR (ky tang)) xa hoi. thieu nien bach tuoc ((van hanh) OR (va danh)) de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su cac ((ky lang) OR (ky tang)) xa hoi. thieu nien bach tuoc ((van hanh) or (va danh)) de cua tre".
• Adding a wildcard symbol may retrieve word variants: su cac ((ky lang) OR (ky tang)) xa hoi. thieu nien bach tuoc ((van hanh) or (va danh)) de cua tre*.