Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va thanh » gia thanh, ban thanh, va tinh
van hanh » van thanh, ban hanh, van anh
sach vu » sach va, sach tu, sach uu
va hanh » va danh, ban hanh, dao hanh
cua tre » cua te, cuu tre, cua triet
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
vu nang » vuc nang, va nang, vu dang
va cam » va cham, va cac, va cao
de cua » le cua, te cua, dieu cua

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

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