Perhaps you should try some spelling variations:
pham duy » pham duc
vat hanh » vat thanh, van hanh, va hanh
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ro » nang co, nang ho, nang ra
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
cuu tre » cua tre, cau treo
ro hoi » co hoi, o hoi, mo hoi

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 ky nang ro hoi. hieu ve pham duy vat hanh vi ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ro hoi. hieu ve pham duy vat hanh vi ((cuu tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ro hoi. hieu ve pham duy vat hanh vi ((cuu tre) or (cau tren))*.