Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thanh van » thanh san, thanh toan, thanh phan
van cua » vang cua, ban cua, dan cua
thuc va » thuc vat, thuc dan, thuc day
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
qua cac » cua cac
cua tre » cua te, cuu tre, cua triet
tuc va » truc va, tuc xa, duc va
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach ty nang ((x hoi) or (o hoi)). hieu qua cac ((tuc va) OR (thuc va)) thanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ty nang ((x hoi) OR (o hoi)). hieu qua cac ((tuc va) OR (thuc va)) thanh van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ty nang ((x hoi) or (o hoi)). hieu qua cac ((tuc va) OR (thuc va)) thanh van cua tre".
• Adding a wildcard symbol may retrieve word variants: thuat sach ty nang ((x hoi) or (o hoi)). hieu qua cac ((tuc va) OR (thuc va)) thanh van cua tre*.