Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thanh ve » hanh ve, thanh va, thanh vien
thanh le » thinh le, thanh de, thanh liem
hieu van » hieu va, thien van, lieu va
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
van cam » van nam, van lam, van cau
ly nang » ky nang, ly hang, ly vang
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, v nang, may nang

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 ((y nang) OR (ly nang)) xa hoi. hieu van cam duc van ((thanh le) or (thanh ve)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((y nang) OR (ly nang)) xa hoi. hieu van cam duc van ((thanh le) OR (thanh ve)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((y nang) OR (ly nang)) xa hoi. hieu van cam duc van ((thanh le) or (thanh ve)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((y nang) OR (ly nang)) xa hoi. hieu van cam duc van ((thanh le) or (thanh ve)) cua tre*.