Perhaps you should try some spelling variations:
va thanh » ban thanh, va tinh, le thanh
dang cau » hang cau, bang cau, dang mau
tu sach » thu sach, te sach, tu cach
cau luc » cau truc, cau phuc
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
su sach » so sach, vu sach
cuc tre » duc tre, cua tre, cuu tre
ve cau » ke cau, va cau, ve cac

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 (su sach)) ky dang cau hoi. hieu ve cau luc ((va thanh) OR (gia thanh)) tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky dang cau hoi. hieu ve cau luc ((va thanh) OR (gia thanh)) tai cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky dang cau hoi. hieu ve cau luc ((va thanh) OR (gia thanh)) tai cuc tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky dang cau hoi. hieu ve cau luc ((va thanh) OR (gia thanh)) tai cuc tre*.