Perhaps you should try some spelling variations:
thanh va » thanh van, hanh va, thanh ha
va thanh » gia thanh, ban thanh, va tinh
su sach » so sach, vu sach
cam thu » cac thu, ca thu, cam phu
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
nang xa » nang x, lang xa, nang ma
va cua » va chua, via cua, ca cua

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 (tang ma)) hoi. hieu ve ((cam thu) OR (nam thu)) va thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (tang ma)) hoi. hieu ve ((cam thu) OR (nam thu)) va thanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (tang ma)) hoi. hieu ve ((cam thu) OR (nam thu)) va thanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (tang ma)) hoi. hieu ve ((cam thu) OR (nam thu)) va thanh va cua tre*.