Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh de » hanh ve, hanh kem
hanh di » hanh vi, hang di, danh di
cam hoc » cao hoc, am hoc, cam hoa
cua tre » cua te, cuu tre, cua triet
o lang » hoa lang, hoi lang
v lang » va lang, _ lang, van lang
va cam » va cham, va cac, va cao

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 ((v lang) or (o lang)) xa hoi. lieu va cam hoc va ((hanh di) or (hanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((v lang) OR (o lang)) xa hoi. lieu va cam hoc va ((hanh di) OR (hanh de)) cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ((v lang) or (o lang)) xa hoi. lieu va cam hoc va ((hanh di) or (hanh de)) cua tre*.