Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hanh vai » hanh va, hanh tai, hanh van
lang mai » lang dai, lang hai, lang man
van nhan » van phan, danh nhan, van khanh
cua tre » cua te, cuu tre, cua triet
mai hoi » mai khoi, dai hoi, lai hoi
ky lang » ky nang, ky dang, ky tang
cai ky » cao ky, cac ky, cam ky
luc va » duc va, tuc va, loc va
tu cai » tu cac, tu can, tu bai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cai ky lang mai hoi. hieu ((van nhan) or (van thanh)) luc va ((hanh vai) OR (hanh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cai ky lang mai hoi. hieu ((van nhan) OR (van thanh)) luc va ((hanh vai) OR (hanh vi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cai ky lang mai hoi. hieu ((van nhan) or (van thanh)) luc va ((hanh vai) OR (hanh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu cai ky lang mai hoi. hieu ((van nhan) or (van thanh)) luc va ((hanh vai) OR (hanh vi)) cua tre*.