Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
cham luu » cham cuu, chat lua, phap luu
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
luu van » cuu van, luan van, luu hanh
vi cua » vai cua, di cua
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (toc sach)) ky nang x hoi. ((hieu va) or (hieu van)) cham luu van hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) ky nang x hoi. ((hieu va) OR (hieu van)) cham luu van hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky nang x hoi. ((hieu va) or (hieu van)) cham luu van hanh vi cua te*.