Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh le » thinh le, thanh ve, thanh de
toc sach » hoc sach, doc sach, thuoc sach
luu van » cuu van, luan van, luu hanh
cam luu » tam luu
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
ly nang » ky nang, ly hang, ly vang
ma hoi » mai hoi, ma hoa, me hoi
va cam » va cham, va cac, va cao
le cua » ly cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ly nang ((ma hoi) or (xa hoi)). hieu va cam luu van thanh le cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ly nang ((ma hoi) OR (xa hoi)). hieu va cam luu van thanh le cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ly nang ((ma hoi) or (xa hoi)). hieu va cam luu van thanh le cua tre*.