Perhaps you should try some spelling variations:
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
cam luc » cau luc
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
dang xa » dang xay, dang ha, dang va
cua tre » cua te, cuu tre, cua triet
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: su sach ky ((dang xa) or (lang xa)) hoi. hieu va ((cam luc) or (cam xuc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((dang xa) OR (lang xa)) hoi. hieu va ((cam luc) OR (cam xuc)) va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((dang xa) or (lang xa)) hoi. hieu va ((cam luc) or (cam xuc)) va hanh vi cua tre*.