Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
viec ban » viec lam, viec va, viec tai
thuc cao » thuoc cao, thuc co, thuc can
viec dan » viec dang, viec dat, viec tang
cao dan » cao dang, cao danh, cac dan
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, 5 hoi

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 ty nang ((x hoi) OR (x ho)). nhieu ((viec dan) or (viec ban)) thuc cao dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang ((x hoi) OR (x ho)). nhieu ((viec dan) OR (viec ban)) thuc cao dan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang ((x hoi) OR (x ho)). nhieu ((viec dan) or (viec ban)) thuc cao dan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang ((x hoi) OR (x ho)). nhieu ((viec dan) or (viec ban)) thuc cao dan vi cua tre*.