Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
thanh vai » thanh hai, thanh tai, thanh oai
sang tao » hang tai
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, pham duc
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky ((nang cao) or (sang tao)) roi. hieu ve cam duc va ((thanh vai) OR (thanh van)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((nang cao) OR (sang tao)) roi. hieu ve cam duc va ((thanh vai) OR (thanh van)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((nang cao) or (sang tao)) roi. hieu ve cam duc va ((thanh vai) OR (thanh van)) cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((nang cao) or (sang tao)) roi. hieu ve cam duc va ((thanh vai) OR (thanh van)) cua tre*.