Perhaps you should try some spelling variations:
tu sach » thu sach, te sach, tu cach
va hanh » van hanh, va thanh, va danh
cam luc » cam xuc, cau luc
hieu va » lieu va
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc 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)) ky lang xa hoi. ((hieu va) or (hieu qua)) cam luc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky lang xa hoi. ((hieu va) OR (hieu qua)) cam luc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) ky lang xa hoi. ((hieu va) or (hieu qua)) cam luc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) ky lang xa hoi. ((hieu va) or (hieu qua)) cam luc va hanh vi cua tre*.