Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
va thanh » gia thanh, ban thanh, va tinh
van quan » van ban
doc sach » hoc sach, nuoc sach, dac sac
cao hoi » cau hoi, co hoi, cao hoc
ty nang » ky nang, ty xang, ty hang
van tai » von tai, van tuan
san cua » sang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, truc va, tuc xa

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

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