Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
cua triet » cua viet, su triet, va triet
cau tren » cu tren, dau tren, ca tren
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cam duc » cam xuc, cao duc, pham duc
nang xa » lang xa, nang ma, mang xa
van cam » van nam, van lam, van cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thien ((nang xa) or (nang x)) hoi. hieu van cam duc va thanh vi ((cua triet) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thien ((nang xa) OR (nang x)) hoi. hieu van cam duc va thanh vi ((cua triet) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach thien ((nang xa) or (nang x)) hoi. hieu van cam duc va thanh vi ((cua triet) or (cau tren))*.