Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
vu cham » va cham, vu kham, tu cham
ve cham » va cham, ve chat, ve chim
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cua tre » cua te, cuu tre, cua triet
soc va » hoc va, loc va, doc 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 ky ((nang xa) or (nang ma)) hoi. hieu ((ve cham) OR (vu cham)) soc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang ma)) hoi. hieu ((ve cham) OR (vu cham)) soc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) or (nang ma)) hoi. hieu ((ve cham) OR (vu cham)) soc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang ma)) hoi. hieu ((ve cham) OR (vu cham)) soc va hanh vi cua tre*.