Perhaps you should try some spelling variations:
va thanh » ban thanh, va tinh, le thanh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cau loc » hau loc, cau hoc, cau luc
hieu va » lieu va, hieu qua
hieu ve » hieu van
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
vi cua » vai cua, di cua

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 ky sang ma hoa. ((hieu ve) or (hieu va)) cau loc ((va thanh) OR (gia thanh)) vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ma hoa. ((hieu ve) OR (hieu va)) cau loc ((va thanh) OR (gia thanh)) vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang ma hoa. ((hieu ve) or (hieu va)) cau loc ((va thanh) OR (gia thanh)) vi cua vat".
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ma hoa. ((hieu ve) or (hieu va)) cau loc ((va thanh) OR (gia thanh)) vi cua vat*.