Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
dau tren » dau tien, dat tren, dau tieng
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau
xuc ban » duc ban, cuc ban, quoc ban
hanh ve » hanh vi, hanh va, hanh kem
ve dau » va dau, ve du, ke dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((tu cach) or (tu cac))) or (toc sach)) ky nang xa hoi. hieu van cam xuc ban hanh ve dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu cach) OR (tu cac))) OR (toc sach)) ky nang xa hoi. hieu van cam xuc ban hanh ve dau tren.
• Adding a wildcard symbol may retrieve word variants: ((((tu cach) or (tu cac))) or (toc sach)) ky nang xa hoi. hieu van cam xuc ban hanh ve dau tren*.