Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » thien van, lieu va, hieu ve
va thanh » gia thanh, ban thanh, va tinh
thanh va » thanh van, hanh va, thanh ha
so sach » so sanh, bo sach, co sach
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
cuu tre » cua tre, cau tren, cau treo
va cuu » va cau, va chu, va huu
x hoi » xa hoi, o hoi, x ho

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

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