Perhaps you should try some spelling variations:
chat truc » cau truc, chat xuc
thu sach » tu sach, thuat sach, thuoc sach
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
va chat » van chat, va phat, cao chat
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang xa » lang xa, nang ma, mang xa
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky ((nang xa) OR (nang x)) hoi. hieu va chat truc ((va danh) or (va hanh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang xa) OR (nang x)) hoi. hieu va chat truc ((va danh) OR (va hanh)) dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang xa) OR (nang x)) hoi. hieu va chat truc ((va danh) or (va hanh)) dai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang xa) OR (nang x)) hoi. hieu va chat truc ((va danh) or (va hanh)) dai cua tre*.