Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
van cam » van nam, van lam, van cau
duc man » duc manh, duc tan, duc mau
duc van » duc va, duc tan, duc manh
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: su sach ky ((nang xa) or (nang x)) hoi. hieu van cam ((duc man) or (duc van)) thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (nang x)) hoi. hieu van cam ((duc man) OR (duc van)) thanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (nang x)) hoi. hieu van cam ((duc man) or (duc van)) thanh dai cua tre*.