Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
cac duc » cac du, cao duc, cac dac
cuu tre » cau tren, cau treo
sach ky » sac ky, sach y, sach ty
va danh » va dinh, va dan, va hanh
sang ma » tang ma, nang ma, sang tao
hieu ve » hieu va, hieu van
ky sang » ky nang, ky dang, ky tang
cua tre » cua te, cua triet, dua tren
ve cac » va cac, vien cac
va dao » ca dao
ma hoi » mai hoi, xa hoi, ma hoa

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 hoi. hieu ve cac duc ((va danh) or (va dao)) lai ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ma hoi. hieu ve cac duc ((va danh) OR (va dao)) lai ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky sang ma hoi. hieu ve cac duc ((va danh) or (va dao)) lai ((cuu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang ma hoi. hieu ve cac duc ((va danh) or (va dao)) lai ((cuu tre) OR (cua tre))*.