Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
su sach » vu sach
van cua » vang cua, ban cua, dan cua
lam duc » lam duoc, nam duoc, lam dung
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet

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

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