Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
ban thanh » ban hanh, ban hang
lam duoc » luat duoc, lam thuoc, tao duoc
nam duoc » nam thuoc, da duoc, dat duoc
hieu van » hieu va, thien van, lieu va
vai cua » dai cua, hai cua, lai cua
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
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: tu sach ky ((nang xa) OR (nang x)) hoi. hieu van ((lam duoc) or (nam duoc)) ban thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang x)) hoi. hieu van ((lam duoc) OR (nam duoc)) ban thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) OR (nang x)) hoi. hieu van ((lam duoc) or (nam duoc)) ban thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) OR (nang x)) hoi. hieu van ((lam duoc) or (nam duoc)) ban thanh vai cua tre*.