Perhaps you should try some spelling variations:
su sach » so sach, vu 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
van cac » van hac, van cau, dan cac
van bac » van ban, van bao, van hac
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
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 ((nang xa) or (lang xa)) hoi. hieu ((van cac) OR (van bac)) truc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (lang xa)) hoi. hieu ((van cac) OR (van bac)) truc va hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (lang xa)) hoi. hieu ((van cac) OR (van bac)) truc va hanh vi cua tre*".