Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu vien » hieu hien, hieu viec, hieu tieng
thu sach » tu sach, thuat sach, thuoc sach
cua viet » ca viet, hoa viet, cua vat
sach ty » sach y, sach tu, sach thu
nang co » nang cao, nang doc, nang noi
ty nang » ky nang, ty xang, ty hang
co hoi » co hoc, co loi
loc va » hoc va, luc va
vi cua » vai cua, di 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 ty nang co hoi. ((hieu vien) OR (thieu nien)) bach ((duc va) or (loc va)) hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang co hoi. ((hieu vien) OR (thieu nien)) bach ((duc va) OR (loc va)) hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang co hoi. ((hieu vien) OR (thieu nien)) bach ((duc va) or (loc va)) hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang co hoi. ((hieu vien) OR (thieu nien)) bach ((duc va) or (loc va)) hanh vi cua viet*.