Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
van tham » van thanh, van tuan, van chat
hieu van » hieu va, thien van, lieu va
tham tuc » tham thuc, thai tuc, nham thuc
doc sach » hoc sach, nuoc sach, dac sac
nang xa » nang x, lang xa, nang ma
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
di cua » dai cua, doi cua, de 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) or (doc sach)) ky nang xa hoi. hieu van tham tuc ((va hanh) or (va dan)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky nang xa hoi. hieu van tham tuc ((va hanh) OR (va dan)) di cua tre.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ky nang xa hoi. hieu van tham tuc ((va hanh) or (va dan)) di cua tre*.