Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van dang » van dong, van nang, van dan
van dung » van dong, xay dung, tin dung
thai cua » than cua, tai cuc, tri cua
sach ky » sac ky, sach y, sach ty
van bac » van bao, van hac, dan bac
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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 nang o hoi. thien ((van bac) or (van ban)) nuoc ((van dang) OR (van dung)) thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang o hoi. thien ((van bac) OR (van ban)) nuoc ((van dang) OR (van dung)) thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang o hoi. thien ((van bac) or (van ban)) nuoc ((van dang) OR (van dung)) thai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang o hoi. thien ((van bac) or (van ban)) nuoc ((van dang) OR (van dung)) thai cua tre*.