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
thu sach » thuat sach, thuoc sach, thu hoach
dang mai » dang hai, dang mau, dang bai
tu sach » su sach, te sach, tu cach
van cua » vang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
ky dang » ky nang, ky danh
mai hoa » mai khoa, ma hoa, dai hoa
ca dua » cay dua, ca cua, ca da
ca dan » cac dan, ca dao

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) OR (thu sach)) ky dang mai hoa. hieu van ((ca dua) or (ca dan)) ban thanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky dang mai hoa. hieu van ((ca dua) OR (ca dan)) ban thanh van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky dang mai hoa. hieu van ((ca dua) or (ca dan)) ban thanh van cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky dang mai hoa. hieu van ((ca dua) or (ca dan)) ban thanh van cua tre*.