Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
sang tao » hang tai
vai cua » dai cua, hai cua, lai cua
cau cua » cau qua, ca cua, cu cua
cau dua » cau qua, ca dua, cay dua
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, nang ma, mang may
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 ((sang ma) or (sang tao)) hoa. hieu van ((cau dua) OR (cau cua)) ban thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((sang ma) OR (sang tao)) hoa. hieu van ((cau dua) OR (cau cua)) ban thanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((sang ma) or (sang tao)) hoa. hieu van ((cau dua) OR (cau cua)) ban thanh vai cua tre*".