Perhaps you should try some spelling variations:
nang dau » hang dau, xang dau, nang du
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
dau hoi » cau hoi, dai hoi, dan hoi
ve cham » va cham, ve chat, vu cham
va danh » va dinh, va dan, va hanh
danh va » doanh va, hanh va, anh va
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. 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. hieu ((ve cai) OR (ve cham)) ly va danh va cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang dau hoi. hieu ((ve cai) or (ve cham)) ly va danh va cua tre*.