Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
dang mai » dang hai, dang mau, dang bai
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hai cua » thai cua, dai cua, hoi cua
quoc va » duoc va, quoc gia, quoc oai
duc ban » duc tan, duc van, dua ban
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky dang mai hoi. hieu va cam ((duc ban) or (((quoc va) OR (nuoc va)))) thanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dang mai hoi. hieu va cam ((duc ban) OR (((quoc va) OR (nuoc va)))) thanh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dang mai hoi. hieu va cam ((duc ban) or (((quoc va) OR (nuoc va)))) thanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky dang mai hoi. hieu va cam ((duc ban) or (((quoc va) OR (nuoc va)))) thanh hai cua tre*.