Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
ky lang » ky nang, ky dang, ky tang
ky danh » ky anh, ky dang
hieu va » hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((ky lang) or (ky danh)) xa hoi. ((hieu va) or (lieu va)) cac nuoc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky lang) OR (ky danh)) xa hoi. ((hieu va) OR (lieu va)) cac nuoc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach ((ky lang) or (ky danh)) xa hoi. ((hieu va) or (lieu va)) cac nuoc va hanh vi cua tre*.