Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
danh va » doanh va, hanh va, anh va
va danh » va dinh, va dan, va hanh
ve cham » va cham, ve chat, vu cham
sach ty » sach y, sach tu, sach thu
dau hoi » cau hoi, dan hoi, dau noi
dai hoi » dai hoc, dai hai, dai moi
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
ve cai » va cai, ve cac, ve tai
va cua » va chua, via cua, ca 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 ty nang ((dau hoi) OR (dai hoi)). hieu ((ve cai) or (ve cham)) ly va danh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((dau hoi) OR (dai hoi)). hieu ((ve cai) OR (ve cham)) ly va danh va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((dau hoi) OR (dai hoi)). hieu ((ve cai) or (ve cham)) ly va danh va cua tre*".