Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
thanh vai » thanh van, thanh tai, thanh oai
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
dua ban » dia ban, cua ban, qua ban
cau dua » cau qua, cau cua, ca dua
van cau » van dau, van hau, van chat
ky dang » ky nang, ky danh
ky sang » ky nang, ky tang, duy sang
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) OR (ky dang)) ma hoa. hieu van cau dua ban ((thanh vai) or (thanh hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky sang) OR (ky dang)) ma hoa. hieu van cau dua ban ((thanh vai) OR (thanh hai)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky sang) OR (ky dang)) ma hoa. hieu van cau dua ban ((thanh vai) or (thanh hai)) cua tre*".