Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
pham duy » pham duc
su sach » so sach, vu sach
va hanh » va thanh, va danh, ban hanh
ve pham » vi pham, v pham, ve phan
sach ly » sach y, sach lo, sach ty
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
sang ma » tang ma, nang ma, sang tao
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de 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 ly ((nang xa) or (sang ma)) hoi. hieu ve pham duy ((va hanh) OR (van hanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly ((nang xa) OR (sang ma)) hoi. hieu ve pham duy ((va hanh) OR (van hanh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly ((nang xa) or (sang ma)) hoi. hieu ve pham duy ((va hanh) OR (van hanh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ly ((nang xa) or (sang ma)) hoi. hieu ve pham duy ((va hanh) OR (van hanh)) di cua tre*.