Perhaps you should try some spelling variations:
pham duy » pham duc
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
ly nang » ky nang, ly hang, ly vang
nang co » nang cao, nang doc, nang noi
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
va hanh » van hanh, va thanh, va danh
co hoi » co hoc, co loi
duy va » duy vat, duy van, day va
vi cua » vai cua, di cua

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) or (su sach)) ly nang co hoi. hieu ve pham duy va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ly nang co hoi. hieu ve pham duy va hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ly nang co hoi. hieu ve pham duy va hanh vi cua viet*.