Perhaps you should try some spelling variations:
hieu ket » hieu kem, thien ket, lien ket
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
cau luc » cau truc, cau phuc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
cua tu » cua tuc, cua su, cua cu

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 xa) or (lang xa)) hoi. hieu ket cau luc va hanh vi ((cua tre) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (lang xa)) hoi. hieu ket cau luc va hanh vi ((cua tre) OR (cua tu)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (lang xa)) hoi. hieu ket cau luc va hanh vi ((cua tre) or (cua tu))*.